scholarly journals A novel pathway for outer membrane protein biogenesis in Gram‐negative bacteria

2015 ◽  
Vol 97 (4) ◽  
pp. 607-611 ◽  
Author(s):  
Mark Jeeves ◽  
Timothy J. Knowles
2005 ◽  
Vol 187 (18) ◽  
pp. 6499-6508 ◽  
Author(s):  
Karsten R. O. Hazlett ◽  
David L. Cox ◽  
Marc Decaffmeyer ◽  
Michael P. Bennett ◽  
Daniel C. Desrosiers ◽  
...  

ABSTRACT The outer membrane of Treponema pallidum, the noncultivable agent of venereal syphilis, contains a paucity of protein(s) which has yet to be definitively identified. In contrast, the outer membranes of gram-negative bacteria contain abundant immunogenic membrane-spanning β-barrel proteins mainly involved in nutrient transport. The absence of orthologs of gram-negative porins and outer membrane nutrient-specific transporters in the T. pallidum genome predicts that nutrient transport across the outer membrane must differ fundamentally in T. pallidum and gram-negative bacteria. Here we describe a T. pallidum outer membrane protein (TP0453) that, in contrast to all integral outer membrane proteins of known structure, lacks extensive β-sheet structure and does not traverse the outer membrane to become surface exposed. TP0453 is a lipoprotein with an amphiphilic polypeptide containing multiple membrane-inserting, amphipathic α-helices. Insertion of the recombinant, nonlipidated protein into artificial membranes results in bilayer destabilization and enhanced permeability. Our findings lead us to hypothesize that TP0453 is a novel type of bacterial outer membrane protein which may render the T. pallidum outer membrane permeable to nutrients while remaining inaccessible to antibody.


2012 ◽  
Vol 287 (15) ◽  
pp. 11740-11750 ◽  
Author(s):  
Yongbin Xu ◽  
Arne Moeller ◽  
So-Young Jun ◽  
Minho Le ◽  
Bo-Young Yoon ◽  
...  

Gram-negative bacteria are capable of expelling diverse xenobiotic substances from within the cell by use of three-component efflux pumps in which the energy-activated inner membrane transporter is connected to the outer membrane channel protein via the membrane fusion protein. In this work, we describe the crystal structure of the membrane fusion protein MexA from the Pseudomonas aeruginosa MexAB-OprM pump in the hexameric ring arrangement. Electron microscopy study on the chimeric complex of MexA and the outer membrane protein OprM reveals that MexA makes a tip-to-tip interaction with OprM, which suggests a docking model for MexA and OprM. This docking model agrees well with genetic results and depicts detailed interactions. Opening of the OprM channel is accompanied by the simultaneous exposure of a protein structure resembling a six-bladed cogwheel, which intermeshes with the complementary cogwheel structure in the MexA hexamer. Taken together, we suggest an assembly and channel opening model for the MexAB-OprM pump. This study provides a better understanding of multidrug resistance in Gram-negative bacteria.


2005 ◽  
Vol 280 (19) ◽  
pp. 18562-18567 ◽  
Author(s):  
Ranjeeta Hari-Dass ◽  
Chandrabala Shah ◽  
David J. Meyer ◽  
John G. Raynes

Author(s):  
Qingfeng Guan ◽  
Biswajit Bhowmick ◽  
Archana Upadhyay ◽  
Qian Han

: Outer membrane protein A (OmpA) is a unique outer membrane protein which is abundantly present in the outer membrane of Gram‐negative bacteria. OmpA is a transmembrane structural protein with a conserved amino acid sequence among different bacteria. This protein is involved in a number of functions like adhesion, toxicity, invasiveness, and biofilm formation in Gram-negative bacteria. Many studies have proposed that OmpA could be a therapeutic target for bacterial infection. Our review focusses on the studies involving recent development in the structure and functions of OmpA and further discussing its potential as a therapeutic target for bacterial infection.


2011 ◽  
Vol 286 (31) ◽  
pp. 27792-27803 ◽  
Author(s):  
Reinhard Albrecht ◽  
Kornelius Zeth

Sign in / Sign up

Export Citation Format

Share Document