The irreversible inactivation of ribonucleotide reductase from Escherichia coli by superoxide radicals

FEBS Letters

Nivière, Vincent²  Gaudu, Philippe²  Kauppi, Björn³  Pétillot, Yves¹  Fontecave, Marc² 

[1] Institut de Biologie Structurale, 41 avenue des Martyrs, 38027 Grenoble Cedex 1, France;Laboratoire d' Etudes Dynamiques et Structurales de la Sélectivité, UMR CNRS 5616, Université Joseph Fourier, BP 53, 38041 Grenoble cedex 9, France;Department of Molecular Biology, Swedish University of Agricultural Sciences, Biomedical Center, Box 590, S-75124, Uppsala, Sweden

关键词: Superoxide radical;    Flavin reductase;    Ribonucleotide reductase;    Tyrosyl radical;    Escherichia coli;   

DOI  :  10.1016/0014-5793(96)00480-2

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The expression of superoxide dismutase in all aerobic living organisms supports the concept that superoxide radicals are toxic species. However, because of the limited chemical reactivity of superoxide, the mechanisms of this toxicity are still uncertain. Protein R2, the small component of ribonucleotide reductase, a key enzyme for DNA synthesis, is shown here to be irreversibly inactivated during incubation with an enzymatic generator of superoxide radicals, at neutral pH. During inactivation the essential tyrosyl radical of protein R2 is irreversibly destroyed. Full protection is afforded by superoxide dismutase. It is proposed that coupling between superoxide radicals and the radical protein R2 generates oxidized forms of tyrosine, tyrosine peroxide and 3,4-dihydroxyphenylalanine.

【 授权许可】

Unknown