Tubulin-blocked state of VDAC studied by polymer and ATP partitioning

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• 作者：Philip A. Gurnev^a ; Tatiana K. Rostovtseva ; ^a ; ^{rostovtt@mail.nih.gov"" rel=""nofollow} ; Sergey M. Bezrukov^a
• 关键词：Voltage-dependent anion channel ; Selectivity ; PEG ; Mitochondria ; Microtubule ; Planar lipid bilayer
• 刊名：FEBS Letters
• 出版年：2011
• 出版时间：21 July 2011
• 年：2011
• 卷：585
• 期：14
• 页码：2363-2366
• 全文大小：595 K

文摘

Recently reported functional interaction between voltage-dependent anion channel of the outer mitochondrial membrane, VDAC, and dimeric tubulin is observed as a reversible channel blockage. Using partitioning of poly-(ethylene glycol)s of different molecular weights and reversal potential measurements, we probe the size and ion selectivity of the fully open and tubulin-blocked states of VDAC reconstituted into planar lipid bilayers. While the effective radius of the channel decreases by only a factor of 1.34 ± 0.15, the selectivity reverses from initially anionic to cationic. Directly measuring ATP partitioning we demonstrate that these changes prohibit ATP from entering the channel in its tubulin-blocked state.