Structural basis of outer membrane protein insertion by the BAM complex

Article

关键词: BARREL ASSEMBLY MACHINERY;    ESCHERICHIA-COLI BAMB;    CRYSTAL-STRUCTURE;    EVOLUTIONARY CONSERVATION;    ESSENTIAL COMPONENT;    IN-VITRO;    BIOGENESIS;    SEQUENCE;    DOMAIN;    SIMULATIONS;   

DOI  :  10.1038/nature17199

来源: SCIE

【 摘 要 】

All Gram-negative bacteria, mitochondria and chloroplasts have outer membrane proteins (OMPs) that perform many fundamental biological processes. The OMPs in Gram-negative bacteria are inserted and folded into the outer membrane by the beta-barrel assembly machinery (BAM). The mechanism involved is poorly understood, owing to the absence of a structure of the entire BAM complex. Here we report two crystal structures of the Escherichia coli BAM complex in two distinct states: an inward-open state and a lateral-open state. Our structures reveal that the five polypeptide transport-associated domains of BamA form a ring architecture with four associated lipoproteins, BamB-BamE, in the periplasm. Our structural, functional studies and molecular dynamics simulations indicate that these subunits rotate with respect to the integral membrane beta-barrel of BamA to induce movement of the beta-strands of the barrel and promote insertion of the nascent OMP.

【 授权许可】

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