Original scientific paper

Crystallographic Study of Mutant Lysl20Leu Xenopus laevis Cu,Zn Superoxide Dismutase

Dijana Matak-Vinković ; Dipartimento di Genetica e Microbiologia, Universita' di Pavia, Via Abbiategrasso, 207, 27100 Pavia, Italy
Martino Bolognesi ; Dipartimento di Genetica e Microbiologia, Universita' di Pavia, Via Abbiategrasso, 207, 27100 Pavia, Italy
Andrea Battistoni ; Dipartimento di Biologia, Universita' di Roma »Tor Vergata« and INFM, Via della Ricerca Scientifica, 00133 Roma, Italy
Alessandro Coda ; Dipartimento di Genetica e Microbiologia, Universita' di Pavia, Via Abbiategrasso, 207, 27100 Pavia, Italy
Kristina Djinovic-Carugo ; European Molecular Biology Laboratory, Postfach 10.2209, D-69012 Heidelberg, Germany

Abstract

Theoretical calculations and experimental measurements on the Xenopus laevis Cu,Zn superoxide dismutase (XSODB) wild-type protein and on some of its engineered mutants showed that the electrostatic arrangement around the active site channel plays a fundamental role in determining the catalytic properties of the en-zyme. Lysl20, which lies on the lip of the active site channel, about 11 Å from the catalytic copper ion, influences the enzyme electrostatic environment and binding selectivity. Neutralization of this residue has the effect of decreasing the activity of the enzyme versus the negatively charged substrate. In order to get precise information about the mutated residue and its effects on the structure of the engineered protein, the crystal structure of single site Lysl20Leu mutant XSODB was determined at 2.0 Å resolution, and refined to an R-factor value of 0.181. The structure of Lysl20Leu mutant XSODB is little affected by the amino-acid substitution, suggesting that the main effect of the mutation is perturbation of the electrostatic properties of the SOD catalytic center.

Keywords

superoxide dismutase; enzyme; protein crystallography

Hrčak ID:

132161

URI

https://hrcak.srce.hr/132161

Publication date:

1.9.1999.

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