Structure-Based Engineering of Lithium-Transport Capacity in an Archaeal Sodium–Calcium Exchanger

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• 作者：Bosmat Refaeli ; Moshe Giladi ; Reuben Hiller ; Daniel Khananshvili
• 刊名：Biochemistry
• 出版年：2016
• 出版时间：March 29, 2016
• 年：2016
• 卷：55
• 期：12
• 页码：1673-1676
• 全文大小：291K
• ISSN：1520-4995

文摘

Members of the Ca²⁺/cation exchanger superfamily (Ca²⁺/CA) share structural similarities (including highly conserved ion-coordinating residues) while exhibiting differential selectivity for Ca²⁺, Na⁺, H⁺, K⁺, and Li⁺. The archaeal Na⁺/Ca²⁺ exchanger (NCX_Mj) and its mammalian orthologs are highly selective for Na⁺, whereas the mitochondrial ortholog (NCLX) can transport either Li⁺ or Na⁺ in exchange with Ca²⁺. Here, structure-based replacement of ion-coordinating residues in NCX_Mj resulted in a capacity for transporting either Na⁺ or Li⁺, similar to the case for NCLX. This engineered protein may serve as a model for elucidating the mechanisms underlying ion selectivity and ion-coupled alternating access in NCX and similar proteins.