Structural Chemistry & Crystallography Communication

Crystal structures of a polypeptide processing and secretion transporter

International Conference on Applied Crystallography
October 16-17, 2017 | Chicago, USA

David Lin

Iowa State University, USA

Posters & Accepted Abstracts: Struct Chem Crystallogr Commun

DOI: 10.21767/2470-9905-C1-003

Abstract

Bacteria secrete peptides and proteins to communicate, to poison competitors, and to manipulate host cells. In Gram-positive bacteria, peptidase-containing ABC transporters (PCATs) function both as maturation proteases and as exporters for quorumsensing or antimicrobial polypeptides. In Gram-negative bacteria, PCATs interact with two other membrane proteins to form the type 1 secretion system. We showed here the first crystal structures of PCAT1 from Clostridium thermocellum in two different conformations. These structures, accompanied by biochemical data, show that the translocation pathway is a large �±-helical barrel sufficient to accommodate small folded proteins. ATP binding alternates access to the transmembrane pathway and regulates the protease activity, thereby coupling substrate processing to translocation.