Assembly of the Type II Secretion System such as Found in Vibrio cholerae Depends on the Novel Pilotin AspS

PLoS Pathogens

Anthony W. Purcell¹  Timothy J. Evans¹  Eva Heinz¹  Rhys A. Dunstan¹  Robert N. Pike¹  Roy M. Robins-Browne²  Konstantin V. Korotkov²  Judyta Praszkier³  Richard A. Strugnell⁴  Trevor Lithgow⁵  Lakshmi C. Wijeyewickrema⁶ 

[1] Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Australia;Department of Microbiology and Immunology, The University of Melbourne, Melbourne, Australia;Department of Molecular and Cellular Biochemistry and Center for Structural Biology, University of Kentucky, Lexington, Kentucky, United States of America;Monash Institute of Medical Research, Melbourne, Australia;Murdoch Childrens Research Institute, Royal Children's Hospital, Melbourne, Australia;Victorian Bioinformatics Consortium, Monash University, Melbourne, Australia

关键词: Secretin;    Outer membrane proteins;    Vibrio cholerae;    Secretion systems;    Sequence analysis;    Crystal structure;    Sequence alignment;    Klebsiella oxytoca;   

DOI  :  10.1371/journal.ppat.1003117

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

The Type II Secretion System (T2SS) is a molecular machine that drives the secretion of fully-folded protein substrates across the bacterial outer membrane. A key element in the machinery is the secretin: an integral, multimeric outer membrane protein that forms the secretion pore. We show that three distinct forms of T2SSs can be distinguished based on the sequence characteristics of their secretin pores. Detailed comparative analysis of two of these, the Klebsiella-type and Vibrio-type, showed them to be further distinguished by the pilotin that mediates their transport and assembly into the outer membrane. We have determined the crystal structure of the novel pilotin AspS from Vibrio cholerae, demonstrating convergent evolution wherein AspS is functionally equivalent and yet structurally unrelated to the pilotins found in Klebsiella and other bacteria. AspS binds to a specific targeting sequence in the Vibrio-type secretins, enhances the kinetics of secretin assembly, and homologs of AspS are found in all species of Vibrio as well those few strains of Escherichia and Shigella that have acquired a Vibrio-type T2SS.

【 授权许可】

CC BY