Structure of a Fragment of the Bacterial Outer Membrane Protein Assembly Machinery

Abstract

Integral ß-barrel proteins are characteristically found in the outer membranes of mitochondria, chloroplasts, and Gram-negative bacteria. The cellular machine that assembles these proteins is conserved and contains as its principal component an integral membrane protein, called YaeT in E. coli, which has one or more polypeptide transport associated (POTRA) domains. I will talk about the structure of a periplasmic fragment of YaeT comprising four POTRA domains, one of which is unique in containing a site that binds extended peptides. We propose that this POTRA domain facilitates the assembly of ß-barrel proteins in the outer membrane by a mechanism involving ß-strand augmentation.