| atp synthesis catalyzed by purified dccd-sensitive atpase incorporated into reconstituted purple membrane vesicles. | | 1975 | 1031 |
| stimulation of atp synthesis in halobacterium halobium r1 by light-induced or artifically created proton electrochemical potential gradients across the cell membrane. | the relationship between proton movement and phosphorylation in halo-bacterium halobium r1 has been investigated under anaerobic conditions. the light-induced changes in the bacteriorhodopsin are accompanied by proton movements across the membrane which result in ph changes in the suspending medium. the initial alkaline shift is shown to be closely paralleled by (and hence correlated with) atp synthesis. acidification of the medium in the presence of valinomycin, under conditions of low external ... | 1976 | 2313 |
| an improved synthetic growth medium for halobacterium cutirubrum. | | 1976 | 3277 |
| comparison of purple membrane from halobacterium cutirubrum and halobacterium halabium. | direct comparison of purple membrane preparations from halobacterium cutirubrum and halobacterium halobium was carried out. both preparations were found to be essentially identical with respect to their molecular weight, retinal content, lipid composition, fingerprinting of peptides from peptide digestion, electron micrographs and x-ray diffraction patterns, and behaviour as a light-activated proton pump. thus, there would appear to be no species differences in the purple membranes from these tw ... | 1976 | 4105 |
| regulation of cell volume and ion concentrations in a halobacterium. | changes in cell volume and ion content of a halobacterium species are described in terms of the nacl concentration (0.5--3.5m) and ph(4-8) of the suspending medium. cell volume, per unit content of protein of bacteria in stationary phase cultures, rose as the nacl of the growth medium was increased. logarithmic-phase bacteria shrank as the ph fell from 7 to 5.5. these changes are characteristic of bacteria with a moderate or rapid rate of o2 consumption. starving (i.e. nonmetabolizing) bacteria, ... | 1976 | 4624 |
| light-induced glutamate transport in halobacterium halobium envelope vesicles. ii. evidence that the driving force is a light-dependent sodium gradient. | illumination of cell envelope vesicles from h. halobium causes the development of protonmotive force and energizes the uphill transport of glutamate. although the uncoupler, p-trifluoromethoxycarbonyl cyanide phenylhydrazone (fccp), and the membrane-permeant cation, triphenylmethylphosphonium (tpmp+), are inhibitory to the effect of light, the time course and kinetics of the production of the energized state for transport, and its rate of decay after illumination, are inconsistent with the idea ... | 1976 | 5106 |
| on the regulatory properties of a halophilic malic enzyme from halobacterium cutirubrum. | the nadp-linked malic enzyme from halobacterium cutirubrum is strongly inhibited by acetyl-coa and nadh, and rather weakly inhibited by oxaloacetate and glyoxylate, in the presence of very high kcl concentrations (3 m), considered physiological for the extremely halophilic bacteria. | 1976 | 5287 |
| technology of biomolecular design, with experiments on light control of the photochemical cycle in halobacterium halobium. | | 1976 | 5311 |
| light-induced membrane potential and ph gradient in halobacterium halobium envelope vesicles. | illumination of envelope vesicles prepared from halobacterium halobium cells causes translocation of protons from inside to outside, due to the light-induced cycling of bacteriorhodopsin. this process results in a ph gradient across the membranes, an electrical potential, and the movements of k+ and na+. the electrical potential was estimated by following the fluorescence of a cyanine dye, 3,3'-dipentyloxadicarbocyanine. illumination of h. halobium vesicles resulted in a rapid, reversible decrea ... | 1976 | 6040 |
| light-induced changes of the ph gradient and the membrane potential in h. halobium. | | 1976 | 6333 |
| light-driven proton translocations in halobacterium halobium. | the purple membrane of halobacterium halobium acts as a light-driven proton pump, ejecting protons from the cell interior into the medium and generating electrochemical proton gradient across the cell membrane. however, the type response of cells to light as measured with a ph electrode in the medium consists of an initial net inflow of protons which subsides and is then replaced by a net outflow which exponentially approaches a new lower steady state ph level. when the light turned off a small ... | 1976 | 7322 |
| an estimation of the light-induced electrochemical potential difference of protons across the membrane of halobacterium halobium. | the light-dependent uptake of triphenylmethylphosphonium (tpmp+) and of 5,5-dimethyloxazolidine-2,4-dione (dmo) by starved purple cells of halobacterium halobium was investigated. dmo uptake was used to calculate the ph difference (deltaph) across the membrane, and tpmp+ was used as an index of the electrical potential difference, deltapsi. under most conditions, both in the light and in the dark, the cells are more alkaline than the medium. in the light at ph 6.6, deltaph amounts to 0.6-0.8 ph ... | 1976 | 9137 |
| passive potassium ion permeability of halobacterium halobium cell envelope membranes. | cell envelope vesicles, prepared from halobacterium halobium, were loaded with 3 m kcl, suspended in 3 m nacl, and the loss of k+ was followed at various temperatures. the arrhenius plot of the k+-efflux rates shows a break at 30 degrees c, with higher energy of activation above the break. this temperature dependence is consistent with earlier studies of chain motions in liposomes prepared from isolated lipids. the efflux of k+ is more rapid with increasing ph between ph 5 and 7. since these ves ... | 1976 | 9154 |
| existence of electrogenic hydrogen ion/sodium ion antiport in halobacterium halobium cell envelope vesicles. | illumination causes the extrusion of protons from halobacterium halobium cell envelope vesicles, as a result of the action of light on bacteriorhodopsin. the protonmotive force developed is coupled to the active transport of na+ out of the vesicles. the light-dependent ion fluxes in these vesicles were studied by following changes in the external ph, in the fluorescence of the dye, 3,3'-dipentyloxadicarbocyanine, in the 22na content of the vesicles, and in 3hdibenzyldimethylammonium (dda+) accum ... | 1976 | 9978 |
| flash photometric experiments on the photochemical cycle of bacteriorhodopsin. | the photochemical reaction cycle of bacteriorhodopsin was investigated by means of flash photometric methods. three different intermediates with absorption maxima at about 630 nm, 411 nm, and 646 nm could be detected. kinetic data of the occurrence of these intermediates were obtained from isolated purple membrane in different mediums and from intact halobacteria. an activation energy of 14.1 +/- 0.4 kcal-mol-1 and of about 19 kcal-mol-1 for formation of bacteriorhodopsin 411 and of bacteriorhod ... | 1975 | 10022 |
| light-dark conformational states in bacteriorhodopsin. | | 1976 | 11791 |
| bacteriorhodopsin depleted of purple membrane lipids. | | 1976 | 11792 |
| bacteriorhodopsin: biphasic kinetics of phototransients and of light-induced proton transfer by sub-bacterial halobacterium halobium particles and by reconstituted liposomes. | | 1976 | 12006 |
| biphasic nature of the light-dependent transport of c14-alanine into halobacterium holobium cells. | biphase character of photoinduced ph change in h. halobium r1 suspension cells is shown: in the first illumination period ph rises and only afterwards it decreases. ph increase is accompanied by the introduction of c14-alanine into the cells, while the decrease by its yield up to the level lower than the "dark" one ("negative" photoeffect). the bi-phase character of transport processes seems to be explained by the reversible character of light-dependent bacteriorodopsin proton pump in h. halobiu ... | 1976 | 12838 |
| light-depending rubidium transport in intact halobacterium halobium cells. | the uptake of rubidium in intact halobacterium halobium cells was followed, and found to be light-dependent. the exchange process is slow, the steady-state rate of 86rb+/rb+ exchange being given by k. = 6.3 - 10(-4) min-1. starved cells exhibited a faster rate than unstarved cells. the influx of 86rb+ was almost completely blocked in the presence of proton conductors (cccp, fccp, and sf 6847), and was sensitive to the presence of the permeant cation tpmp+. valinomycin very slightly increased the ... | 1977 | 14683 |
| the photochemical cycle of bacteriorhodopsin. | the reaction cycle of bacteriorhodopsin in the purple membrane isolated from halobacterium halobium has been studied by optical absorption spectroscopy using low-temperature and flash kinetic techniques. after absorption of light, bacteriohodopsin passes through at least five distinct intermediates. the temperature and ph dependence of the absorbance changes suggests that branch points and/or reversible steps exist in this cycle. flash spectroscopy in the presence of a ph-indicating dye shows th ... | 1977 | 15873 |
| photochemical and chemical studies on the chromophore of bacteriorhodopsin. | the chromophore (purple complex) of bacteriorhodopsin is reduced by sodium borohydride upon illumination to rphv with a three-peaked absorption band at 360 nm. treatment of this reduction product with ultraviolet light or acid yields a modified product from which retro-retinyllysine can be obtained by alkaline hydrolysis. no reduction of the 412 nm complex was found. under specific conditions the purple complex equilibrates with a photochemically active 460 nm form that can be reduced by borohyd ... | 1977 | 15874 |
| proton translocation by atpase and bacteriorhodopsin. | stable membrane proteins and lipids are convenient to study biomembranes. two stable proton translocating proteins were purified and reconstituted into vesicles capable of proton translocation. one was a thermostable atpase (tf0-f1) of thermophilic bacterium ps3 and the other was rhodopsin of halobacterium halobium. tf0-f1 was composed of a proton pump moiety (tf1) and a proton channel moiety (tf0). tf1 was the first membrane atpase which was crystallized and reconstituted from its five polypept ... | 1977 | 15875 |
| light-dependent cation gradients and electrical potential in halobacterium halobium cell envelope vesicles. | vesicles can be prepared from halobacterium halobium cell envelopes, which contain properly oriented bacteriorhodopsin and which extrude h+ during illumination. the ph difference that is generated across the membranes is accompanied by an electrical potential of 90-100 mv (interior negative) and the movements of other cations. among these is the efflux of na+, which proceeds against its electrochemical potential. the relationship between the size and direction of the light-induced ph gradient an ... | 1977 | 15877 |
| light-activated amino acid transport in halobacterium halobium envelope vesicles. | vesicles prepared from halobacterium halobium cell envelopes accumulate amino acids in response to light-induced electrical and chemical gradients. nineteen of 20 commonly occurring amino acids have been shown to be actively accumulated by these vesicles in response to illumination or in response to an artificially created na-gradient. sodium-activated amino acid transport for 18 of these amino acids has been shown to occur in direct response to the protonmotive force generated. glutamate is tra ... | 1977 | 15878 |
| light energy conservation processes in halobacterium halobium cells. | in halobacterium halobium, proton pumping driven by light or by respiration generates an electrochemical potential difference across the membrane. energy storage in this form is only transient. cellular energy transducers competing with proton leaks stabilize this free energy as high energy phosphate bonds, electrochemical potential of other ions, and chemical potential of amino acids and possibly other chemical species. the ph changes induced by light or by respiration in cell suspensions are c ... | 1977 | 15879 |
| purple membrane vesicles: morphology and proton translocation. | purple membrane vesicles prepared by different techniques differ widely in their morphology and ability to establish a proton gradient in the light. the procedures used to prepare active vesicles do not completely dissociate the purple membrane and thus preserve a preferential orientation of the protein, while most of the lipid is exchanged for added lipid. responses to illumination are largely determined by the size of the vesicles and the degree to which bacteriorhodopsin is preferentially ori ... | 1977 | 17009 |
| water relations in single cells. | | 1977 | 17871 |
| apparent pk of photolabile proton binding to bacteriorhodopsin. | | 1977 | 19017 |
| rhodopsin and the visual process. | | 1977 | 19062 |
| bacteriorhodopsin-mediated photophosphorylation in halobacterium halobium. | the rate of halobacterial photophosphorylation was found to be a linear function of light intensity over a wide range (between 1 and 20 mw/cm2). at higher light intensities (above 25 mw/cm2) the atp-synthesizing system itself limits the maximal rate of photophosphorylation. the optimal external ph range for this type of photophosphorylation is between ph 6.2 and 7.2 external. the photophosphorylation rate is directly proportional to the bacteriorhodopsin content of the cells. the quantum require ... | 1977 | 19249 |
| transport in halobacterium halobium: light-induced cation-gradients, amino acid transport kinetics, and properties of transport carriers. | | 1977 | 20536 |
| two possible roles of bacteriorhodopsin; a comparative study of strains of halobacterium halobium differing in pigmentation. | | 1977 | 20882 |
| photogeneration of a 2-vector transmembrane proton gradient in halobacterium halobium r1 cells. | analysing 4 phases of light-dependent change of ph in cell suspension of h. halobium r1 it has been found that an increase of ph i when light is switched on and a decrease of ph ii during further illumination are proportional to the light effect and are energy-dependent. neutralization of these changes (phases iii and iv) proceeds spontaneously in the darkness. these data show that the transmembrane gradient of protons is generated in two directions--delta ph and +delta ph, simultaneous presence ... | 1977 | 20986 |
| quantitative aspects of energy conversion in halobacteria. | | 1977 | 21098 |
| the direction of light-induced ph changes in purple membrane suspensions. influence of ph and temperature. | | 1977 | 21811 |
| effect of ionophoric compounds on aqueous suspensions of purple membrane. | | 1977 | 21814 |
| luminescence of bacteriorhodopsin from halobacterium halobium and its connection with the photochemical conversions of the chromophore. | | 1977 | 22347 |
| photoinduced inhibition and stimulation of respiration in cells of halobacterium halobiums kinetics, action spectra, relationship to photoinduction of deltaph. | along with the inhibition illumination also causes the stimulation of the respiration of h. halobium r1 cells. when light is switched off photoinhibition of respiration (pir) decays much faster (tau 1/2=12 sec) than photostimulation (psr) (tau 1/2=60 sec). this allows the evaluation of the contribution of the each phase into the total change of the respiration rate. pir prevails in neutral and alkaline media (at ph 6.8 the amplitude ratio of psr/pir=0.3). at the same conditions light induced alk ... | 1977 | 22357 |
| formations of electrochemical proton gradient and adenosine triphosphate in proteoliposomes containing purified adenosine triphosphatase and bacteriorhodopsin. | proteoliposome vesicles containing both bacteriorhodopsin of halobacterium halobium and h+-translocating atpase ec 3.6,1.3 of a thermophilic bacterium, ps3, (tf0-f1) were reconstituted by either the dialysis method or the sonication method. generation of the electrochemical proton gradient (deltamuh+) in these vesicles was measured using 9-aminoacridine for estimation of the chemical (deltaph) component and 8-anilinonaphthalene sulfonate for the electrical (deltaphi) component). in illuminated b ... | 1977 | 23379 |
| energy characteristics of the stages of photo-dependent transport of 14c-alanine in halobacterium halobium r1 cells. | the energy of light is utilized by halobacterium halobium r1 only at the very beginning of illumination at the same time as the transport of protons into the cells, as follows from comparing the data of photophosphorylation and light-dependent transport. the release of protons by the cells on further illumination suggests that the photoprocess and the accumulation of energy by the cells are being uncoupled. the primary transport of 15c-alanine in the course of illumination is caused directly by ... | 1977 | 23486 |
| time resolution of the intermediate steps in the bacteriorhodopsin-linked electrogenesis. | | 1978 | 24553 |
| sulfate-mediated affinity chromatography on nadp+-sepharose of glutamate dehydrogenase from halophilic bacteria and of glucose-6-phosphate dehydrogenase from escherichia coli. | an improved synthesis of the 8-(6-aminohexyl)amino derivative of nadp+ is described for use in affinity chromatography. the binding of glutamate dehydrogenase isolated from halobacterium of the dead sea on a column of sepharose linked to this nadp+ derivative could be drastically enhanced by addition of sulfate (1m) and provided a tool for partially purifying the enzyme from a crude extract. a similar finding is reported for glucose-6-phosphate dehydrogenase in crude extracts of escherichia coli ... | 1978 | 25766 |
| studies of an acid-induced species of purple membrane from halobacterium halobium. | a new spectral species of the purple membrane of halobacterium halobium has been observed below ph 3.2. the formation of this new species is temperature-dependent and is favoured by increasing temperature up to the physiological range of the organism. the rate of formation at ph 3.0 and 22 degrees c is 7.9 x 10-3s-1. the spectral distribution and temperature-dependence of the new species suggest that it may be phototransiet o, stabilized by low ph. flash-photolytic experiments in the ph range 7. ... | 1978 | 26337 |
| bacteriorhodopsin: lipid environment and conformational changes. | the polar lipids of the purple membrane were exchanged for different phosphatidylcholine species. the resulting complexes had the same protein to lipid-phosphorus ratio as the natural membrane, but only about 0.5-1.0 mole of original lipid was still present per mole of bacteriorhodopsin. in such complexes the bacteriorhodopsin photocycle is slowed down 10-20 times, but the strong protein-protein interaction is not abolished. due to the slow rate of the photocycle we were able to measure in the l ... | 1978 | 26925 |
| mechanism of generation and regulation of photopotential by bacteriorhodopsin in bimolecular lipid membrane. | photoelectric properties of bacteriorhodopsin incorporated into a bimolecular lipid membrane were investigated with special regard to the mechanism of photoelectric field generation. it was shown that besides its proton pump and electric generator functions bacteriorhodopsin works as a possible molecular regulator of the light-induced membrane potential. when a bimolecular lipid membrane containing bacteriorhodopsin is continuously illuminated in its main visible absorption band, and afterwards ... | 1978 | 28756 |
| the pk of schiff base deprotonation in bacteriorhodopsin. | | 1978 | 29615 |
| potassium uniport and atp synthesis in halobacterium halobium. | light-driven potassium ion uptake in halobacterium halobium is mediated by bacteriorhodopsin. this uptake is charge-balanced by sodium ions and not by proton release. light-induced shifts in concentrations of divalent cations were found to be negligible. the transient changes in extracellular ph (alkaline overshoot) can be understood by the concomitant processes of atp synthesis, proton/sodium exchange and potassium uptake. the driving force of potassium ion uptake is the membrane potential, no ... | 1978 | 29755 |
| demonstration of coupling between the protonmotive force across bacteriorhodopsin and the flow through its photochemical cycle. | | 1978 | 29778 |
| bacteriorhodopsin vesicles. an outline of the requirements for light-dependent h+ pumping. | a systematic study was performed to determine under which conditions bacteriorhodopsin can be applied as an energy generator in reconstituted systems. it is concluded that reconstitution of an active light-driven proton pump is possible over a wide range of conditions. high extents (per bacteriorhodopsin molecule) of proton uptake by reconstituted vesicles are found at a high lipid to protein ratio, after long sonication and at high ph. no active proton pump is obtained if reconstitution is atte ... | 1978 | 31174 |
| light-induced ph changes inside bacteriorhodopsin vesicles as measured by 31 p nmr. | 31p nmr has been used to measure light-induced ph changes inside bacteriorhodopsin vesicles containing entrapped sodium glucose-6-phosphate. reversible light-induced ph changes were observed at various ph values. the results indicate that our vesicle preparations were not homogeneous with respect to the generation of ph gradients. | 1978 | 31176 |
| salt reversal of the acid-induced changes in purple membrane from halobacterium halobium. | | 1978 | 31300 |
| kinetic analysis of light-induced ph changes in bacteriorhodopsin-containing particles from halobacterium halobium. | | 1978 | 31901 |
| bacteriorhodopsin induces a light-scattering change in halobacterium halobium. | when suspensions of halobacterium halobium are exposed to bright light, the light-scattering properties of the bacteria change. this light-scattering response can produce a transmission decrease of about 1% throughout the red and near-infrared region. the action spectrum for the light-scattering response appropriately matches the absorption spectrum of bacteriorhodopsin. the response is eliminated by cyanide p-trifluoro-methoxyphenylhydrazone, a proton ionophore, and by triphenylmethylphosphoniu ... | 1978 | 32181 |
| the low ph species of bacteriorhodopsin. structure and proton pump activity. | | 1979 | 33836 |
| electrophoretic mobility of membrane fragments on a sucrose gradient. application to isolated purple membrane fragments from halobacterium halobium. | | 1979 | 34337 |
| bacteriorhodopsin and the purple membrane of halobacteria. | | 1979 | 35226 |
| a channel mechanism for electrogenic ion pumps. | a model of active ion transport is analyzed in which an essential part of the pumps molecule is an ion channel. ion translocation in the channel is described as a series of jumps between binding sites which are separated by energy barriers. pumping action results from a transient energy-dependent modification of the barrier structure of the channel and requires only minor conformational changes of the pump molecule. this model is applied to the light-driven proton pump of halobacterium and to re ... | 1979 | 35228 |
| gating effects in halobacterium halobium membrane transport. | | 1979 | 35540 |
| the measurement of membrane potential and deltaph in cells, organelles, and vesicles. | | 1979 | 37402 |
| incorporation of purple membrane into vesicles capable of light-stimulated atp synthesis. | | 1979 | 37410 |
| reaction of the purple membrane with a carbodiimide. | purple membrane was reacted with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide at ph 4.5 and 8.0. at ph 4.5, the reaction yields cross-linked bacteriorhodopsin. the cross-linking is inhibited by pretreatment of the membrane with papain, or by the presence of carbohydrazide or glycine ethyl ester in the reaction mixture. the product of the ph 8.0 reaction is not cross-linked, but it displays altered properties. two measures of photochemical activity (light-induced change in proton binding (delta ... | 1979 | 37905 |
| an alternative hypothesis for the direction of hydrogen ion movement and energy transduction in h. halobium. | | 1979 | 38787 |
| effect of acid ph on the absorption spectra and photoreactions of bacteriorhodopsin. | purple membranes (pm) from halobacterium halobium were incorporated into 7.5% polyacrylamide gels to prevent aggregation which occurs in suspensions at low ph. at ph 7.0, the circular dichroism (cd) spectra and visible absorption spectra of light- and dark-adapted bacteriorhodopsin (br558, respectively) and the flash photolysis cycle of br568 in gels were essentially the same as those in pm suspensions. titration of the gels with hydrochloric acid showed the transition to a form absorbing at 605 ... | 1979 | 39590 |
| light-induced conductivity changes in purple membrane suspensions. | small light-induced changes in the conductivity of light-adapted purple membrane suspended in strong electrolyte solutions were detected. the method used involved modulated light and a phase sensitive detector and it allowed us to detect accurately changes as small as 0.0001% in the conductivity of the suspension. the light-induced conductivity changes turned out to be composed of at least two different event: a small fast increase in conductivity (tau approximately 2 ms) followed by a slower an ... | 1979 | 39648 |
| the consequences of a deuterium exchange test on proposed mechanisms for the purple membrane proton pump. | | 1979 | 40821 |
| proton movements in response to a light-driven electrogenic pump for sodium ions in halobacterium halobium membranes. | | 1979 | 40979 |
| characterization of the light-driven sodium pump of halobacterium halobium. consequences of sodium efflux as the primary light-driven event. | | 1979 | 40987 |
| evidence for a model of regeneration of a protonated species, br, from a phototransient, m, in the photochemical cycle of bacteriorhodopsin from halobacterium halobium [proceedings]. | | 1979 | 41777 |
| active site structure of bacteriorhodopsin and mechanism of action. | | 1979 | 42400 |
| bacteriorhodopsin monomers pump protons. | | 1979 | 42560 |
| spectral transitions in purple membranes from halobacterium halobium. i. effect of preliminary illumination on photochemical processes. | the effect of preliminary illumination of purple membranes by yellow light on the difference spectra of short-lived intermediates has been studied. it has been found that changes of the optical density of two of these intermediates, which have the maxima of the difference spectrum at 412 nm and 650 nm, coincides well with the kinetics off the known reversible transitions of the main band of the purple membrane absorption (560 570), i.e., 13-cis-trans transitions. the changes at 412 nm and 650 nm ... | 1978 | 45332 |
| the quantum yield of flash-induced proton release by bacteriorhodopsin-containing membrane fragments. | the quantum yield of proton release by bacteriorhodopsin was measured from volume changes after excitation of purple membrane fragments by short flashes. at low ionic strengths, about 0.25 mol of protons is released per einstein absorbed. this agrees well with quantum yields reported recently for the conversion of bacteriorhodopsin into a metastable state (m) that absorbs near 412 nm. however, the quantum yield of proton release increases gradually with increasing ionic strength; it plateaus wit ... | 1979 | 45396 |
| bacteriorhodopsin in model membranes. a new component of the displacement photocurrent in the microsecond time scale. | a quasi-short-circuit (tunable voltage clamp) measurement method with microsecond time resolution was applied to a bacteriorhodopsin model membrane formed by a novel interfacial technique. a new component (b1) of the displacement photocurrent was recorded: it has no detectable latency at an instrumental time constant of 1.5 museconds, and persists at 5 degrees c. in addition, a slower component (b2) of opposite polarity inhibited by low temperature (5 degrees c) and low ph (ph = 3.0) was recorde ... | 1979 | 45397 |
| dynamics of ph-induced spectral changes in bacteriorhodopsin. | the kinetics of the spectral shift induced in bacteriorhodopsin by low ph are investigated by using the rapid-mixing, stopped-flow technique. the generation of the acid form of the chromophore (a605) occurs in two distinct steps: a fast process (t1/2i = 21 +/- 4 ms) is followed by a much slower reaction (t1/2ii = 6 +/- 2 s). the observations are interpreted in terms of neutralization of an acid group in the neighborhood of the retinyl chromophore, the double-staged kinetics being attributed to c ... | 1979 | 45398 |
| light-induced leucine transport in halobacterium halobium envelope vesicles: a chemiosmotic system. | halabacterium halobium cell envelope vesicles accumulate l-[14-c]leucine during illumination, against a large concentration gradient. leucine uptake requires na-+ and is optimal in kcl-loaded vesicles resuspended in kcl-nacl solution (1.5 m:1.5 m). half-maximal transport is seen at 1 x 10-minus 6 m leucine. in the dark the accumulated leucine is rapidly and exponentially lost from the vesicles. the action spectrum and the light-intensity dependence indicate that the transport is related to the e ... | 1975 | 50859 |
| reconstitution of biological molecular generators of electric current. bacteriorhodopsin. | 1. photoinduced generation of electric current by bacteriorhodopsin, incorporated into the planar phospholipid membrane, has been directly measured with conventional electrometer techniques. 2. two methods for bacteriorhodopsin incorporation have been developed: (a) formation of planar membrane from a mixture of decane solution of phospholipids and of the fraction of violet fragments of the halobacterium halobium membrane (bacteriorhodopsin sheets), and (b) adhesion of bacteriorhodopsin-containi ... | 1976 | 62754 |
| immunochemical characterization of ferredoxin from halobacterium of the dead sea. | | 1978 | 76564 |
| the effect of antibiotics on the photocycle and protoncycle of purple membrane suspensions. | the interrelation was studied between the phototransient absorbing maximally at 412 nm (m412) and light-induced proton release under steady-state conditions in aqueous suspensions of 'purple membrane' derived from halobacterium halobium. the decay of m412 was slowed down by the simultaneous application of the ionophoric antibiotics valinomycin and beauvericin. the former had only slight activity alone and the latter was effective only in conjunction with valinomycin. the steady-state concentrati ... | 1979 | 83163 |
| light-induced ph changes in sub-bacterial particles of halobacterium halobium. effects of ionophores. | the kinetics of light-induced acidification and of the subsequent dark-induced alkalization in suspensions of sub-bacterial particles of halobacterium halobium may be expressed as the sum of two exponentials, indicating two processes (eisenbach, m., bakker, e.p., korenstein, r. and caplan, s.r. (1976) febs lett. 71, 228--232). we studied the effects of carbonyl cyanide p-trifluoromethyoxy phenyl-hydrazone, nigericin, gramicidin d, valinomycin, and monactin on the extents and the rate constants o ... | 1979 | 83878 |
| physico-chemical basis of ion transport through biological membranes: ionophores and ion channels. | | 1979 | 85552 |
| quantitative study of the energy conversion in halobacterium halobium [proceedings]. | | 1979 | 94791 |
| [the moderate halophilic bacteria]. | | 1979 | 95613 |
| photobehavior of microorganisms: a biophysical approach. | | 1978 | 96724 |
| the 5 s rna.protein complex from an extreme halophile, halobacterium cutirubrum. studies on the rna-protein interaction. | | 1979 | 105009 |
| biological effects of magnetic fields: studies with microorganisms. | five bacteria and one yeast were grown in magnetic fields of 50-900 gauss with frequencies of 0-0.3 hz and square, triangular, or sine waveform. growth of these microorganisms could be stimulated or inhibited depending upon the field strength and frequency of the pulsed magnetic field. spore germination and mutation frequency were unaffected by the magnetic fields used in this study. | 1979 | 119572 |
| acetyl phosphatidylethanolamine in the reconstitution of ion pumps. | acetyl phosphatidylethanolamine was compared with phosphatidylethanolamine in the reconstitution of several biological membrane activities with the following results. 1. the proton pump reconstituted with the purple membrane of halobacterium halobium and acetyl phosphatidylethanolamine was quite active. however, some differences in the kinetic properties, particularly in the decay rate, were noted between vesicles reconsituted with phosphatidylethanolamine and acetyl phosphatidylethanolamine. 2. ... | 1975 | 122978 |
| energy coupling in the active transport of amino acids by bacteriohodopsin-containing cells of halobacterium holobium. | growth of halobacterium halobium under illumination with limiting aeration induces bacteriorhodopsin formation and renders the cells capable of photophosphorylation. cells depleted of endogenous reserves by a starvation treatment were used to investigate the means by which energy is coupled to the active transport of [14c]proline, -leucine, and -histidine. proline was readily accumulated by irradiated cells under anaerobiosis even when the photophosphorylation was abolished by the adenosine trip ... | 1976 | 128552 |
| resolution and reconstitution of ion-transport systems. | 1. oxidative phosphorylation was reconstituted with a mitochondrial proton pump (oligomycin-sensitive atpase) and segments of the oxidation chain (cytochrome oxidase or dpnh-q1 reductase). a proton pump of bacteriorhodopsin substituted for the respiratory chain components, giving rise to light-induced atp formation. 2. since oxidative phosphorylation has thus become a special case of the problem of ion translocation in general, we have investigated and reconsituted other pumps. the reconstituted ... | 1975 | 130818 |
| speculations on the evolution of ion transport mechanisms. | primate cells evolved a plasma membrane to restrict the loss of important molecules. the osmotic problems that then arose were solved in one of several ways. of major importance was the evolution of specific ion pumps, to actively extrude those salts whose inward diffusion would have led to swelling and lysis. in addition, these pumps allowed the cell to store energy in the form of ion gradients across the membrane. thus, even in the earliest stages, the evolution of ion transport systems coinci ... | 1976 | 133032 |
| [mechanism of action of the specific inhibitor of respiration and phosphorylation in mitochondria--n-(n,n-di-2-chlorethyl)aminophenylacetic acid]. | an electrophilous inhibitor, p-(n,n-di-2-chloroethyl)amino-phenylacetic acid (i), specifically disturbs the mechanism of respiration and phosphorylation coupling in mitochondria. i inhibits respiration and atpase activity in intact mitochondria and does not affect these processes in mitochondria and submitochondrial particles with partially or completely impaired coupling system. the data obtained show that i inhibits protonophoric function of nadh-ferricianide reductase from submitochondrial pa ... | 1976 | 136999 |
| cf1-dependent restoration of energy-linked reactions reconstituted with a hydrophobic protein from spinach chloroplasts. | | 1977 | 142483 |
| the 5-s rna . protein complex from an extreme halophile, halobacterium cutirubrum. purification and characterization. | a 5-s rna . protein complex has been isolated from the 50-s ribosomal subunit of an extreme halophile, halobacterium cutirubrum. the 50-s ribosomal subunit from the extreme halophile requires 3.4 m k+ and 100 mm mg2+ for stability. however, if the high k+ concentration is maintained but the mg2+ concentration lowered to 0.3 mm, the 5-s rna . protein complex is selectively extracted from the subunit. after being purified on an agarose 0.5-m column the complex had a molecular weight of about 80000 ... | 1978 | 152199 |
| structure and energy-linked activities in reconstituted bacteriorhodopsin--yeast atpase proteoliposomes. | | 1979 | 159663 |
| sensory transduction in halobacterium halobium: retinal protein pigment controls uv-induced behavioral response. | | 1979 | 160706 |
| a spin label study of purple membranes from halobacterium halobium. | | 1975 | 163078 |
| [atp synthesis connected with the functioning of membrane proton pumps at the octane/water interface]. | | 1975 | 166808 |
| [letter: epr study of bacteriorhodopsin-containing systems]. | | 1975 | 173406 |
| [role of phospholipids in the generation of membrane potentials by proteoliposomes]. | closed protein-phospholipid particles (proteoliposomes), obtained by self-assembly method, are capable to generate and to maintain the membrane potential in the case if their protein complex is represented by: a) a complex of mitochondrial atpase; b) a complex of cytochrome oxidase and cytochrome c and c) bacteriorhodopsin from halobacterium halobium; and their phospholipid component is represented by phosphatidylethanolamine or by a mixture of mitochondrial phospholipids. only cytochromoxidase ... | 1975 | 174754 |
| light-stimulated oxygen uptake by vesicles containing cytochrome c oxidase and bacteriorhodopsin. | | 1976 | 182550 |