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NADH PEROXIDASE WITH CYSTEINE-SULFENIC ACID
Structural highlights
FunctionNAPE_ENTFA Peroxidase whose active site is a redox-active cysteine-sulfenic acid. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedIn order to obtain the crystal structure of the flavoprotein NADH peroxidase with its native Cys42-sulfenic acid redox center, a strategy combining reduced exposure of crystals to ambient oxygen and data collection at -160 degrees C was applied. The structure of the native enzyme to 2.8 A resolution is described; these results conclusively establish the existence of the Cys42-sulfenic acid as the functional non-flavin redox center of the peroxidase and provide the first structure for any naturally occurring protein-sulfenic acid. The Cys42-sulfenic acid atoms C alpha-C beta-S gamma-O roughly define a planar arrangement which is stacked parallel to the si face of the FAD isoalloxazine and positions the sulfenyl oxygen atom only 3.3 A from FAD-C4A. His10-N epsilon 2 contributes a hydrogen bond to the sulfenic acid oxygen, at a distance of 3.2 A. Although one oxygen atom (OX1) of the non-native Cys42-sulfonic acid derivative identified in the earlier wild-type peroxidase structure was taken to represent the native Cys42-sulfenic acid oxygen [Stehle, T., Ahmed, S. A., Claiborne, A., & Schulz, G. E. (1991) J. Mol. Biol. 221, 1325-1344], this structure shows that the sulfenic acid oxygen does not occupy this position, nor is it hydrogen-bonded to Cys42-N as was OX1. Comparison of the native Cys42-sulfenic acid structure with that of two-electron reduced glutathione reductase provides an insight into the sulfenic acid FAD charge-transfer interaction observed with both wild-type and His10 mutant peroxidases. A model of the E.NADH intermediate recently observed in stopped-flow analyses of the enzyme [Crane, E. J., III, Parsonage, D., Poole, L. B., & Claiborne, A. (1995) Biochemistry 34, 14114-14124] has also been generated to assist in analyzing the chemical mechanism of sulfenic acid reduction. Structure of the native cysteine-sulfenic acid redox center of enterococcal NADH peroxidase refined at 2.8 A resolution.,Yeh JI, Claiborne A, Hol WG Biochemistry. 1996 Aug 6;35(31):9951-7. PMID:8756456[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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