Structure of the molybdenum site of Rhodobacter sphaeroides biotin sulfoxide reductase.

Published

Journal Article

Conditions for heterologous expression of Rhodobacter sphaeroides biotin sulfoxide reductase in Escherichia coli were modified, resulting in a significant improvement in the yield of recombinant enzyme and enabling structural studies of the molybdenum center. Quantitation of the guanine and the molybdenum as compared to that found in R. sphaeroides DMSO reductase demonstrated the presence of the bis(MGD)molybdenum cofactor. UV-visible absorption spectra were obtained for the oxidized, NADPH-reduced, and dithionite-reduced enzyme. EPR spectra were obtained for the Mo(V) state of the enzyme. X-ray absorption spectroscopy at the molybdenum K-edge has been used to probe the molybdenum coordination of the enzyme. The molybdenum site of the oxidized protein possesses a Mo(VI) mono-oxo site (Mo=O at 1.70 A) with additional coordination by approximately four thiolate ligands at 2.41 A and probably one oxygen or nitrogen at 1.95 A. The NADPH- and dithionite-reduced Mo(IV) forms of the enzyme are des-oxo molybdenum sites with approximately four thiolates at 2.33 A and two different Mo-O/N ligands at 2.19 and 1.94 A.

Full Text

Duke Authors

Cited Authors

  • Temple, CA; George, GN; Hilton, JC; George, MJ; Prince, RC; Barber, MJ; Rajagopalan, KV

Published Date

  • April 11, 2000

Published In

Volume / Issue

  • 39 / 14

Start / End Page

  • 4046 - 4052

PubMed ID

  • 10747793

Pubmed Central ID

  • 10747793

International Standard Serial Number (ISSN)

  • 0006-2960

Digital Object Identifier (DOI)

  • 10.1021/bi9921541

Language

  • eng

Conference Location

  • United States