PMID: 9539706Apr 29, 1998Paper

Role of a critical water in scytalone dehydratase-catalyzed reaction

Proceedings of the National Academy of Sciences of the United States of America
Y J Zheng, T C Bruice

Abstract

Scytalone dehydratase (EC 4.2.1.94) catalyzes the dehydration of two important intermediates in the biosynthesis of melanin, and it functions without metal ions or any cofactors. Using molecular orbital theory, we have examined the role of a critical water molecule in the mechanism of scytalone dehydratase. The water, together with an internal hydrogen bonding, contributes significantly to the stabilization of the transition state (or the enolate intermediate). The role of two active site tyrosines (Tyr-50 and Tyr-30) is (i) to hold the critical water in place so that it may stabilize the transition state without much structural rearrangement during the catalytic reaction, and (ii) to polarize the water, making it a better general acid. The stereochemistry of the scytalone dehydratase-catalyzed dehydration is also discussed.

References

May 1, 1975·European Journal of Biochemistry·P Willadsen, H Eggerer
Jul 7, 1995·Science·A WarshelP A Kollman
Dec 1, 1996·Current Opinion in Structural Biology·G H ReedI Rayment

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Citations

Jun 7, 2000·Organic Letters·G S BasarabY J Zheng
Jul 16, 2015·Journal of Chemical Information and Modeling·Alexander S BaydenMichelle L Lamb
Jun 13, 2015·Critical Reviews in Food Science and Nutrition·Minori Uchimiya

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