气候变化领域集成服务门户(CCPortal): Electrochromic shift supports the membrane destabilization model of Tat-mediated transport and shows ion leakage during Sec transport

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DOI	10.1073/pnas.2018122118
	Electrochromic shift supports the membrane destabilization model of Tat-mediated transport and shows ion leakage during Sec transport
	Asher A.H.; Theg S.M.
发表日期	2021
ISSN	00278424
卷号	118 期号:12
英文摘要	The mechanism and pore architecture of the Tat complex during transport of folded substrates remain a mystery, partly due to rapid dissociation after translocation. In contrast, the proteinaceous SecY pore is a persistent structure that needs only to undergo conformational shifts between “closed” and “opened” states when translocating unfolded substrate chains. Where the proteinaceous pore model describes the SecY pore well, the toroidal pore model better accounts for the high-energy barrier that must be overcome when transporting a folded substrate through the hydrophobic bilayer in Tat transport. Membrane conductance behavior can, in principle, be used to distinguish between toroidal and proteinaceous pores, as illustrated in the examination of many antimicrobial peptides as well as mitochondrial Bax and Bid. Here, we measure the electrochromic shift (ECS) decay as a proxy for conductance in isolated thylakoids, both during protein transport and with constitutively assembled translocons. We find that membranes with the constitutively assembled Tat complex and those undergoing Tat transport display conductance characteristics similar to those of resting membranes. Membranes undergoing Sec transport and those with the substrate-engaged SecY pore result in significantly more rapid electric field decay. The responsiveness of the ECS signal in membranes with active SecY recalls the steep relationship between applied voltage and conductance in a proteinaceous pore, while the nonaccelerated electric field decay with both Tat transport and the constitutive Tat complex under the same electric field is consistent with the behavior of a toroidal pore. © 2021 National Academy of Sciences. All rights reserved.
英文关键词	Electrochromic shift \| twin arginine translocon \| Sec \| protein translocation \| toroidal pore
语种	英语
来源期刊	Proceedings of the National Academy of Sciences of the United States of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/180154
作者单位	Plant Biology Department, University of California, Davis, CA 95616, United States
推荐引用方式 GB/T 7714	Asher A.H.,Theg S.M.. Electrochromic shift supports the membrane destabilization model of Tat-mediated transport and shows ion leakage during Sec transport[J],2021,118(12).
APA	Asher A.H.,&Theg S.M..(2021).Electrochromic shift supports the membrane destabilization model of Tat-mediated transport and shows ion leakage during Sec transport.Proceedings of the National Academy of Sciences of the United States of America,118(12).
MLA	Asher A.H.,et al."Electrochromic shift supports the membrane destabilization model of Tat-mediated transport and shows ion leakage during Sec transport".Proceedings of the National Academy of Sciences of the United States of America 118.12(2021).