Structure of a VirD4 coupling protein bound to a VirB type IV secretion machinery.

ABSTRACT: Type IV secretion (T4S) systems are versatile bacterial secretion systems mediating transport of protein and/or DNA T4S systems are generally composed of 11 VirB proteins and 1 VirD protein (VirD4). The VirB1-11 proteins assemble to form a secretion machinery and a pilus while the VirD4 protein is responsible for substrate recruitment. The structure of VirD4 in isolation is known; however, its structure bound to the VirB1-11 apparatus has not been determined. Here, we purify a T4S system with VirD4 bound, define the biochemical requirements for complex formation and describe the protein-protein interaction network in which VirD4 is involved. We also solve the structure of this complex by negative stain electron microscopy, demonstrating that two copies of VirD4 dimers locate on both sides

SUBMITTER: Redzej A 

PROVIDER: S-EPMC5916273 | biostudies-literature | 2017 Oct

REPOSITORIES: biostudies-literature