Minor pseudopilin self-assembly primes type II secretion pseudopilus elongation.

ABSTRACT: In Gram-negative bacteria, type II secretion systems (T2SS) assemble inner membrane proteins of the major pseudopilin PulG (GspG) family into periplasmic filaments, which could drive protein secretion in a piston-like manner. Three minor pseudopilins PulI, PulJ and PulK are essential for protein secretion in the Klebsiella oxytoca T2SS, but their molecular function is unknown. Here, we demonstrate that together these proteins prime pseudopilus assembly, without actively controlling its length or secretin channel opening. Using molecular dynamics, bacterial two-hybrid assays, cysteine crosslinking and functional analysis, we show that PulI and PulJ nucleate filament assembly by forming a staggered complex in the plasma membrane. Binding of PulK to this complex results in its partial extract

SUBMITTER: Cisneros DA 

PROVIDER: S-EPMC3280553 | biostudies-literature | 2012 Feb

REPOSITORIES: biostudies-literature