segregation of col ib and drd7 into minicells.the wild-type plasmid colib and its mutant drd7 derepressed in conjugation were transferred to escherichia coli k12 p678-54 which produces minicells. fertility functions of drd7 remained derepressed in the new host. p678-54drd7 transmitted the plasmid at a high frequency (28.6%) and it was effectively lysed by the phage if1. significant amounts of 3h-dna segregated from p67854col+ into minicells dependent upon the presence of the plasmid. the depressed plasmid segregated more effectively into mi ...1976779404
reprogramming the infection mechanism of a filamentous phage.when they infect escherichia coli cells, the filamentous phages if1 and fd first interact with a pilus and then target tola as their common receptor. they use the domains n2 and n1 of their gene-3-proteins (g3p) for these interactions but differ in the mechanism of infection. in g3p of phage if1, n1 and n2 are independent modules that are permanently binding-active. g3p of phage fd is usually in a closed state in which n1 and n2 are tightly associated. the tola binding site is thus inaccessible ...201121392130
properties of a filamentous phage which adsorbs to pili coded by plasmids of the inci complex.a filamentous phage, pr64fs, which adsorbs to tips of i pili was isolated. pr64fs is shorter than the i pilus-adsorbing phage if1 and differs from it in plaque morphology. phages pr64fs and ifl are serologically related and, like the latter, pr64fs adsorbs to pili coded by all inc groups of the i plasmid complex.19806106662
covert fi- r factors in fi+ r+ strains of bacteria.the presence of an fi(-) sex factor can be detected by propagation of the i-specific phage if1. by use of this method of detection, a high proportion of strains with fi(+) r factors were shown also to carry an fi(-) factor which was frequently a second r factor. in some doubly r(+) strains, the fi(+) and the fi(-) factor were observed to be transferred independently at conjugation.19694886294
the filamentous phages fd and if1 use different mechanisms to infect escherichia coli.the filamentous phage fd uses its gene 3 protein (g3p) to target escherichia coli cells in a two-step process. first, the n2 domain of g3p attaches to an f pilus, and then the n1 domain binds to tola-c. n1 and n2 are tightly associated, rendering the phage robust but noninfectious because the binding site for tola-c is buried at the domain interface. binding of n2 to the f pilus initiates partial unfolding, domain disassembly, and prolyl cis-to-trans isomerization in the hinge between n1 and n2. ...201021110981
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