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Tubulin‐blocked state of VDAC studied by polymer and ATP partitioning
Author(s) -
Gurnev Philip A.,
Rostovtseva Tatiana K.,
Bezrukov Sergey M.
Publication year - 2011
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2011.06.008
Subject(s) - voltage dependent anion channel , tubulin , biophysics , chemistry , ethylene glycol , selectivity , lipid bilayer , ion channel , membrane potential , microtubule , membrane , biochemistry , bacterial outer membrane , microbiology and biotechnology , biology , organic chemistry , receptor , escherichia coli , gene , catalysis
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.