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Article
The Active Site Sulfenic Acid Ligand in Nitrile Hydratases Can Function as a Nucleophile
Journal of the American Chemical Society
  • Salette Martinez, Loyola University Chicago
  • Rui Wu, Loyola University Chicago
  • Ruslan Sanishvili, Argonne National Laboratory
  • Dali Liu, Loyola University Chicago
  • Richard C. Holz, Marquette University
Document Type
Article
Language
eng
Format of Original
4 p.
Publication Date
1-29-2014
Publisher
American Chemical Society
Original Item ID
DOI: 10.1021/ja410462j
Disciplines
Abstract
Nitrile hydratase (NHase) catalyzes the hydration of nitriles to their corresponding commercially valuable amides at ambient temperatures and physiological pH. Several reaction mechanisms have been proposed for NHase enzymes; however, the source of the nucleophile remains a mystery. Boronic acids have been shown to be potent inhibitors of numerous hydrolytic enzymes due to the open shell of boron, which allows it to expand from a trigonal planar (sp2) form to a tetrahedral form (sp3). Therefore, we examined the inhibition of the Co-type NHase from Pseudonocardia thermophila JCM 3095 (PtNHase) by boronic acids via kinetics and X-ray crystallography. Both 1-butaneboronic acid (BuBA) and phenylboronic acid (PBA) function as potent competitive inhibitors of PtNHase. X-ray crystal structures for BuBA and PBA complexed to PtNHase were solved and refined at 1.5, 1.6, and 1.2 Å resolution. The resulting PtNHase–boronic acid complexes represent a “snapshot” of reaction intermediates and implicate the cysteine-sulfenic acid ligand as the catalytic nucleophile, a heretofore unknown role for the αCys113–OH sulfenic acid ligand. Based on these data, a new mechanism of action for the hydration of nitriles by NHase is presented.
Comments

Published version. Journal of the American Chemical Society, Vol. 136, No. 4 (January 29, 2014): 1186-1189. DOI. © 2014 American Chemical Society. Used with permission.

ACS AuthorChoice - This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes.

Citation Information
Salette Martinez, Rui Wu, Ruslan Sanishvili, Dali Liu, et al.. "The Active Site Sulfenic Acid Ligand in Nitrile Hydratases Can Function as a Nucleophile" Journal of the American Chemical Society (2014) ISSN: 0002-7863
Available at: http://works.bepress.com/richard_holz/93/