conformation of escherichia coli outer membrane protein ompa produced in bacillus subtilis: influence of lipopolysaccharide.the conformation of the outer membrane protein ompa of escherichia coli produced in bacillus subtilis and solubilized in sarkosyl was studied by measuring its ability to bind ompa-specific phage k3 and to inhibit f-mediated conjugation. the partially purified protein was inactive in both of these assays. refolding of the protein in the presence of lipopolysaccharide resulted in preparations with full phage-binding and conjugation-inhibiting capacity, indicating the formation of surface-exposed l ...19938440462
correlation between the expression of an escherichia coli cell surface protein and the ability of the protein to bind to lipopolysaccharide.the ompa gene of escherichia coli codes for a major protein of the outer membrane. when this gene was moved between various unrelated strains (e. coli k-12 and two clinical isolates of e. coli) by transduction, the gene was expressed very poorly. recombinants carrying "foreign" genes produced no ompa protein which could be detected on polyacrylamide gels and became resistant to bacteriophage k3, which uses this protein as receptor. the recombinants were sensitive to host-range mutants of k3, ind ...19806995440
a class of ompa mutants of escherichia coli k12 affected in the interaction of ompa protein and the core region of lipopolysaccharide.a group of ompa mutants of escherichia coli k12 are described which were sensitive to bacteriophage k3 in a background wild-type for lipopolysaccharide (lps). with mutant lps in vivo (lacking some core sugar residues), however, the ompa mutations gave resistance to k3. outer membrane levels of ompa protein were normal or near-normal when the mutations resided in either wild-type or mutant lps backgrounds. strains in which the mutations occurred in a wild-type lps background adsorbed k3 phage at ...19836343781
dna sequence heterogeneity in the genes of t-even type escherichia coli phages encoding the receptor recognizing protein of the long tail fibers.genes (g) 36 and 37 code for the proteins of the distal half of the long tail fibers of phage t4, gene product (gp) 35 links the distal half to the proximal half of this fiber. the receptor, lipopolysaccharide, most likely is recognized by gp37. using as probe a restriction fragment consisting of most of g36 and g37 of phage t4 the genes corresponding to g35, g36, and g37 of phages t2 and k3 (using the e. coli outer membrane proteins ompf and ompa, respectively, as receptors) have been cloned in ...19846092843
dna sequence of genes 38 encoding a receptor-recognizing protein of bacteriophages t2, k3 and of k3 host range mutants.genes 38, which code for a receptor-recognizing protein present at the tip of the long tail fibers, have been sequenced from phages t2, the t-even-type phage k3 and its host range mutants k3hx, k3h1 and k3h1h. the genes from phages t2 and k3 code for proteins consisting of 262 and 260 amino acid residues, respectively. fifty amino-terminal and 25 carboxy-terminal residues are highly conserved. the amino-terminal amino acids are most likely involved in binding to the neighboring protein 37. betwe ...19873302276
t-even-type bacteriophages use an adhesin for recognition of cellular receptors.protein 38 of the escherichia coli phage t4 is thought to be required catalytically for the assembly of the long tail fibers of this phage. it is shown that this protein of phage t2 and the t-even-type phage k3 and ox2 act differently. it was found that nh2-terminal fragments of the protein, expressed from cloned fragments of gene 38 of phage k3, bind to gene 38 amber mutants of phage t2. such phage or t2 gene 38 amber mutants, grown on a non-permissive host, possess a complete set of six tail f ...19873302275
presence of dna, encoding parts of bacteriophage tail fiber genes, in the chromosome of escherichia coli k-12.the classical t-even bacteriophages recognize host cells with their long tail fibers. gene products 35, 36, and 37 constitute the distal moiety of these fibers. the free ends of the tail fibers, which are formed by the co2h terminus of gene product 37, possess the host range determinants. it was found that 4 out of 10 different strains of escherichia coli k-12 contained regions of chromosomal dna which hybridized with a probe consisting of genes 35, 36, and 37 of the t-even phage k3. from one st ...19852993246
outer membrane of escherichia coli k-12: isolation of mutants with altered protein 3a by using host range mutants of bacteriophage k3.a series of mutants has been isolated with alterations to protein 3a of the outer membrane. these mutations map at the previously described con locus as shown by cotransduction with pyrd. most of them do not have detectable levels of protein 3a but are thought to have low levels of altered protein. these mutants have been detected by screening con mutants, isolated as resistant to bacteriophage k3, for their ability to plaque host range mutants of this bacteriophage. these host range phage mutan ...1976783129
inactivation of bacteriophages by protein e, a new major membrane protein isolated from an escherichia coli mutant.pure protein e, obtained after diethylaminoethyl-cellulose chromatography of ethylenediaminetetraacetic acid-triton x-100-solubilized outer membrane proteins of escherichia coli strain jf694, inactivated bacteriophage k3. lipopolysaccharide enhanced bacteriophage inactivation. antibody prepared against purified protein e protected bacteriophage k3 from inactivation by protein e. bacteriophage k3 used a major outer membrane protein, protein ii*, as part of its receptor. we conclude that proteins ...1979368014
structural and functional roles of the surface-exposed loops of the beta-barrel membrane protein ompa from escherichia coli.the n-terminal domain of the ompa protein from escherichia coli, consisting of 170 amino acid residues, is embedded in the outer membrane, in the form of an antiparallel beta-barrel whose eight transmembrane beta-strands are connected by three short periplasmic turns and four relatively large surface-exposed hydrophilic loops. this protein domain serves as a paradigm for the study of membrane assembly of integral beta-structured membrane proteins. in order to dissect the structural and functiona ...199910368142
t-even type phages can change their host range by recombination with gene 34 (tail fibre) or gene 23 (head).t-even type phages recognize their cellular receptors with the tip of their long tail fibres. the gene products involved in receptor recognition are proteins 37 and 38. while screening libraries of phage k3 with a probe of gene 38 from phage t2, a class of weakly hybridizing clones was found in addition to the expected clones of gene 38 of k3. one of these clones was identified as being from gene 23 of the phage which codes for the major head subunit; another clone originated from gene 34, which ...19863025557
concentration of a major outer membrane protein at the cell poles in escherichia coli.autoradiography of cell envelope ghosts obtained from a strain of escherichia coli which lacks two major outer membrane proteins has been used to demonstrate the polar concentration of another major outer membrane protein, ompa protein. the beta-lactam antibiotic cephalexin prevents the insertion of newly synthesized ompa protein into the poles but removal of the antibiotic allows the randomly dispersed protein to migrate to the polar and possibly the septal areas of the cell. labelling of whole ...19846389767
lysis gene t of t-even bacteriophages: evidence that colicins and bacteriophage genes have common ancestors.the lysis gene t of the t-even-like bacteriophage k3 has been cloned and sequenced. the gene codes for a protein with a predicted molecular weight of 25,200. expression of the complete lysis protein was impossible, but peptides complementing t4 amber mutants in t are described. no known lysis protein of other phages is homologous to protein t. also, the escherichia coli phospholipase a is different from protein t. celb, the lysis protein of the colicin e2 operon, shows a similarity to protein t. ...19873597316
architecture of the outer membrane of escherichia coli k12. phase transitions of the bacteriophage k3 receptor complex. 1979391560
direct in situ structural analysis of recombinant outer membrane porins expressed in an ompa-deficient mutant escherichia coli ompa-deficient mutant of an ompf/ompc-free escherichia coli b strain was selected using phage k3. the mutant strain was characterized by sds-gel electrophoresis, immunoblotting, and electron microscopy. all major outer membrane proteins, including ompa, were absent. this strain was then transformed with the plasmid pmy222 encoding the k12 ompf porin or with pblue-script-derived plasmids, encoding the porins ompc, phoe, and maltoporin, respectively. following sds extraction of outer membrane s ...19938003382
ligand-mediated protection against phage lysis as a positive selection strategy for the enrichment of epitopes displayed on the surface of e. coli cells.we present a novel strategy, termed cistem, which allows direct in vivo screening of polypeptides displayed on the surface of e. coli cells by a combination of ligand-mediated protection and phage-mediated selection. the effectiveness of this new approach was demonstrated by displaying the t7.tag on the surface of e. coli as a fusion with the outer membrane protein a, the receptor for bacteriophage k3. a monoclonal t7.tag antibody was used as protective ligand for t7.tag-displaying cells and pha ...200111843180
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