Substrate-induced conformational changes in sarcoplasmic reticulum Ca2+-ATPase probed by surface modification using diethylpyrocarbonate with mass spectrometry.

Ryouhei Narumi, Taibo Yamamoto, Akio Inoue, Toshiaki Arata

Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka, Japan.

FEBS letters 2012 Sep 21

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We have identified 15 residues from the surface of sarcoplasmic reticulum Ca(2+)-pump ATPase, by mass spectrometry using diethylpyrocarbonate modification. The reactivity of 9 residues remained high under all the conditions. The reactivity of Lys-515 at the nucleotide site was severely inhibited by ATP, whereas that of Lys-158 in the A-domain decreased by one-half and increased by five-fold in the presence of Ca(2+) and MgF(4), respectively. These are well explained by solvent accessibility, pK(a) and nearby hydrophobicity of the reactive atom on the basis of the atomic structure. However, the reactivity of 4 residues near the interface among A-, N- and P-domain suggested larger conformational changes of these domains in membrane upon binding of Ca(2+) (Lys-436), ATP (Lys-158) and MgF(4) (His-5, -190, Lys-436). Copyright © 2012 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Citation

Ryouhei Narumi, Taibo Yamamoto, Akio Inoue, Toshiaki Arata. Substrate-induced conformational changes in sarcoplasmic reticulum Ca2+-ATPase probed by surface modification using diethylpyrocarbonate with mass spectrometry. FEBS letters. 2012 Sep 21;586(19):3172-8