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Pathways of electron transfer and proton translocation in the action of superoxide dismutase dimer

Ramasarma, T and Vaigundan, D (2019) Pathways of electron transfer and proton translocation in the action of superoxide dismutase dimer. In: BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, 514 (3). pp. 772-776.

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Official URL: https://doi.org/10.1016/j.bbrc.2019.05.028


Superoxide dismutase, known to gain large rate enhancement on dimerization, forms a homodimer stabilized by hydrogen bonding between a number of internal water molecules and a few amino acid residues at the interface. Within each subunit the beta-sheets provide a sequence of delocalized pi-electron units of peptide bonds alternating with hydrogen bonds referred as pi-H pathway. These pathways in the two subunits in the dimer are interlinked through a chain of four water molecules bridged by hydrogen bonds at the interface. Connecting the two Cu-centers this pi-H pathway can enable rapid electron transfer from one superoxide molecule to the other, crucial for the catalytic reaction and the high rate in the dimer. A proton relay of hydrogen-bonded water molecules in the dimer translocates protons to form the product, hydrogen peroxide. (C) 2019 Elsevier Inc. All rights reserved.

Item Type: Journal Article
Additional Information: Copyright of this article belongs to ACADEMIC PRESS INC ELSEVIER SCIENCE
Keywords: Superoxide dismutase; Copper zinc enzyme; Beta sheets; Dimer; Rate enhancement; pi-H pathway; Proton relay
Department/Centre: Division of Biological Sciences > Biochemistry
Division of Biological Sciences > Molecular Biophysics Unit
Date Deposited: 08 Jul 2019 10:57
Last Modified: 08 Jul 2019 10:57
URI: http://eprints.iisc.ac.in/id/eprint/63122

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