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论文类型：期刊论文

发表时间：2017-11-04

发表刊物：BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS

收录刊物：Scopus、SCIE、PubMed

卷号：493

期号：1

页面范围：152-157

ISSN号：0006-291X

关键字：Bacillus amyloliquefaciens; SDP transporter YknWXYZ; Membrane fusion protein YknX

摘要：Membrane fusion proteins (MFPs) play an essential role in the action of the drug efflux pumps and protein secretion systems in bacteria. The sporulation delaying protein (SDP) efflux pump YknWXYZ has been identified in diverse Bacillus species. The MFP YknX requires the ATP-binding cassette (ABC) transporter YknYZ and the Yipl family protein YknW to form a functional complex. To date, the crystal structure, molecular function and mechanism of action of YknX remain unknown. In this study, to characterize the structural and biochemical roles of YknX in the functional assembly of YknWXYZ from B. amyloliquefaciens, we successfully obtained crystals of the YknX protein that diffracted X-rays to a resolution of 4.4 angstrom. We calculated an experimentally phased map using single-wavelength anomalous diffraction (SAD), revealing that YknX forms a hexameric assembly similar to that of MacA from Gramnegative bacteria. The hexameric assembly of YknX exhibited a funnel-like structure with a central channel and a conical mouth. Functional studies in vitro suggest that YknX can bind directly to peptidoglycan. Our study provides an improved understanding of the assembly of the YknWXYZ efflux pump and the role of YknX in the complex. (C) 2017 Elsevier Inc. All rights reserved.