Structural insights into cardiolipin transfer from the Inner membrane to the outer membrane by PbgA in Gram-negative bacteria

Dong, Haohao, Zhang, Zhengyu, Tang, Xiaodi, Huang, Shihai, Li, Huanyu, Peng, Bo and Dong, Changjiang (2016) Structural insights into cardiolipin transfer from the Inner membrane to the outer membrane by PbgA in Gram-negative bacteria. Scientific Reports, 6. ISSN 2045-2322

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The outer membrane (OM) of Gram-negative bacteria is a unique asymmetric lipid bilayer in which the outer leaflet is composed of lipopolysaccharide (LPS) and the inner leaflet is formed by glycerophospholipid (GPL). The OM plays a fundamental role in protecting Gram-negative bacteria from harsh environments and toxic compounds. The transport and assembly pathways for phospholipids of bacterial OM are unknown. Cardiolipin (CL) plays an important role in OM biogenesis and pathogenesis, and the inner membrane (IM) protein PbgA, containing five transmembrane domains and a globular domain in periplasm has been recently identified as a CL transporter from the IM to the OM with an unknown mechanism. Here we present the first two crystal structures of soluble periplasmic globular domain of PbgA from S. typhimurium and E. coli, which revealed that the globular domains of PbgA resemble the structures of the arylsulfatase protein family and contains a novel core hydrophobic pocket that may be responsible for binding and transporting CLs. Our structural and functional studies shed an important light on the mechanism of CL transport in Gram-negative bacteria from the IM to the OM, which offers great potential for the development of novel antibiotics against multi-drug resistant bacterial infections.

Item Type: Article
Additional Information: © The Author(s) 2016 This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit
Uncontrolled Keywords: bacterial structural biology,transport carrier,x-ray crystallography
Faculty \ School: Faculty of Medicine and Health Sciences > Norwich Medical School
UEA Research Groups: Faculty of Medicine and Health Sciences > Research Groups > Gastroenterology and Gut Biology
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Depositing User: Pure Connector
Date Deposited: 24 Sep 2016 00:26
Last Modified: 20 Mar 2024 13:30
DOI: 10.1038/srep30815


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