A putative proton binding site of plasma membrane H<SUP>+-ATPase identified through homology modelling

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• 作者：Bukrinsky ; Jens T. ; Buch-Pedersen ; Morten J. ; Larsen ; Sine ; Palmgren ; Michael G.
• 关键词：Auto-inhibition ; H<SUP>+-ATPase ; Hydronium ion ; Proton binding site ; Regulatory domain ; Rabbit sarcoplasmic reticulum Ca<SUP>2+-ATPase isoform 1 ; Proton pump ; A-domain ; actuator or anchor domain ; ACA2 ; Arabidopsis thaliana auto-inhibited Ca<SU
• 刊名：FEBS Letters
• 出版年：2001
• 出版时间：April 6, 2001
• 年：2001
• 卷：494
• 期：1-2
• 页码：6-10
• 全文大小：558 K

文摘

We have used the 2.6 Å structure of the rabbit sarcoplasmic reticulum Ca<SUP>2+-ATPase isoform 1a, SERCA1a [Toyoshima, C., Nakasako, M., Nomura, H. and Ogawa, H. (2000) Nature 405, 647–655], to build models by homology modelling of two plasma membrane (PM) H⁺-ATPases, Arabidopsis thaliana AHA2 and Saccharomyces cerevisiae PMA1. We propose that in both yeast and plant PM H⁺-ATPases a strictly conserved aspartate in transmembrane segment (M)6 (D684<sub>AHA2sub>/D730<sub>PMA1sub>), and three backbone carbonyls in M4 (I282<sub>AHA2sub>/I331<sub>PMA1sub>, G283<sub>AHA2sub>/I332<sub>PMA1sub> and I285<sub>AHA2sub>/V334<sub>PMA1sub>) comprise a binding site for H<sub>3sub>O⁺, suggesting a previously unknown mechanism for transport of protons. Comparison with the structure of the SERCA1a made it feasible to suggest a possible receptor region for the C-terminal auto-inhibitory domain extending from the phosphorylation and anchor domains into the transmembrane region.