Role of Sequence Bias in the Topology of the Multidrug Transporter EmrE

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• 作者：Hassane S. Mchaourab ; Sanjay Mishra ; Hanane A. Koteiche ; Sepan H. Amadi
• 刊名：Biochemistry
• 出版年：2008
• 出版时间：August 5, 2008
• 年：2008
• 卷：47
• 期：31
• 页码：7980-7982
• 全文大小：163K
• 年卷期：v.47,no.31(August 5, 2008)
• ISSN：1520-4995

文摘

EmrE is the prototype of small multidrug resistance transporters and has emerged as a model of membrane protein evolution. Analysis of the distances separating symmetry-related site-specific spin labels, correlation of topological sequence bias to C-terminal orientation, to membrane insertion efficiency, and to resistance to ethidium bromide collectively demonstrate that EmrE monomers adopt a parallel topology in the functional dimer. We propose a coupled insertion and assembly model for EmrE in which the favorable energetics of the parallel dimer interface override topological constraints arising from weak asymmetry in positive charge distribution.