Novel Class of Mutations of pilS Mutants, Encoding Plasmid R64 Type IV Prepilin: Interface of PilS-PilV Interactions

Abstract

The type IV pili of plasmid R64 belonging to the type IVB group are required only for liquid mating. They consist of the major and minor components PilS pilin and PilV adhesin, respectively. PilS pilin is first synthesized as a 22-kDa prepilin from the pilS gene and is then processed to a 19-kDa mature pilin by PilU prepilin peptidase. In a previous genetic analysis, we identified four classes of the pilS mutants (T. Horiuchi and T. Komano, J. Bacteriol. 180:4613-4620, 1998). The products of the class I pilS mutants were not processed by prepilin peptidase; the products of the class II mutants were not secreted; in the class III mutants type IV pili with reduced activities in liquid mating were produced; and in the class IV mutants type IV pili with normal activities were produced. Here, we describe a novel class, class V, of pilS mutants. Mutations in the pilS gene at Gly-56 or Tyr-57 produced type IV pili lacking PilV adhesin, which were inactive in liquid mating. Residues 56 and 57 of PilS pilin are suggested to function as an interface of PilS-PilV interactions.

The Type IV Pilus of Plasmid TP114 Displays Adhesins Conferring Conjugation Specificity and Is Important for DNA Transfer in the Mouse Gut Microbiota

“…The predicted PilS topology of TP114 (Fig. S3A) is highly similar to that of PilS from R64, and its primary sequence already contains two cysteines that presumably form a disulfide bond for stabilization ( 42 ), which are therefore not available for labeling. Based on their nucleophilic properties and their relative surface accessibility in the classical “lollipop” PilS fold ( 14 ), 10 serine or threonine residues were selected for cysteine replacement ( Fig.…”

Systematic investigation of recipient cell genetic requirements reveals important surface receptors for conjugative transfer of IncI2 plasmids

“…The pilV gene is followed by multiple DNA cassettes, flanked by rci-recombination motifs, that can be swapped independently or in groups to change the 3'-end of pilV 28 . Depending on T4Pb, between 2 to 8 different PilV variants can be formed, of which one is thought to be displayed at the tip of the pilus 26,29 . PilV variants appear to recognize specific structures on the surface of recipient cells allowing conjugation in unstable environments where mobility, flow forces, and external factors may prevent bacterial interactions 26 .…”

Fímbrias Pil em Escherichia coli enteropatogênica atípica: Caracterização e investigação do papel de PilS e PilV na adesão bacteriana.

“…Entretanto a caracterização fenotípica destas cepas é de suma importância, uma vez que a expressão de genes relacionados à virulência, especialmente os genes fimbriais, é que determinam o potencial patogênico desses isolados (HERNANDES et al, 2011). Dados na literatura demonstram que os genes pil expressam uma fímbria do tipo IV que aparentemente contribui para conjugação plasmidial e adesão bacteriana, além de promover a formação de biofilme através da interação bactéria-bactéria, entre outras funções (SHIMODA et al, 2008). Com base nesses dados, algumas das funções desempenhadas por essa fímbria foram estudadas no presente trabalho.…”