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

Adam Redzej, Marta Ukleja, Sarah Connery, Martina Trokter, Catarina Felisberto-Rodrigues, Adam Cryar, Konstantinos Thalassinos, Richard Hayward, Elena V Orlova, Gabriel Waksman, Apollo-University Of Cambridge Repository, Apollo-University Of Cambridge Repository
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
more » ... 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 of the apparatus, in between the VirB4 ATPases. Given the central role of VirD4 in type IV secretion, our study provides mechanistic insights on a process that mediates the dangerous spread of antibiotic resistance genes among bacterial populations.
doi:10.17863/cam.38118 fatcat:vbklslpj7zgfnl62wvdv37ddkq