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Unusual Constriction Zones in the Major Porins OmpU and OmpT from Vibrio cholerae

DOI: 10.1016/j.str.2018.03.010 DOI Help

Authors: Monisha Pathania (Newcastle University) , Silvia Acosta-gutierrez (University of Cagliari) , Satya Pratyusha Bhamidimarri (University of Cagliari) , Arnaud Basle (Newcastle University) , Mathias Winterhalter (Jacobs University Bremen) , Matteo Ceccarelli (University of Cagliari) , Bert Van Den Berg (Newcastle University)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Structure

State: Published (Approved)
Published: April 2018
Diamond Proposal Number(s): 9948 , 13587

Abstract: The outer membranes (OM) of many Gram-negative bacteria contain general porins, which form nonspecific, large-diameter channels for the diffusional uptake of small molecules required for cell growth and function. While the porins of Enterobacteriaceae (e.g., E. coli OmpF and OmpC) have been extensively characterized structurally and biochemically, much less is known about their counterparts in Vibrionaceae. Vibrio cholerae, the causative agent of cholera, has two major porins, OmpU and OmpT, for which no structural information is available despite their importance for the bacterium. Here we report high-resolution X-ray crystal structures of V. cholerae OmpU and OmpT complemented with molecular dynamics simulations. While similar overall to other general porins, the channels of OmpU and OmpT have unusual constrictions that create narrower barriers for small-molecule permeation and change the internal electric fields of the channels. Together with electrophysiological and in vitro transport data, our results illuminate small-molecule uptake within the Vibrionaceae.

Journal Keywords: outer membrane protein; porin; Vibrio cholerae; crystal structure; OmpU; OmpT; bile salts; electrophysiology; membrane channel

Subject Areas: Biology and Bio-materials

Instruments: I02-Macromolecular Crystallography , I03-Macromolecular Crystallography , I04-1-Macromolecular Crystallography (fixed wavelength) , I04-Macromolecular Crystallography , I24-Microfocus Macromolecular Crystallography