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An active site tyrosine influences the ability of the dimethyl sulfoxide reductase family of molybdopterin enzymes to reduce S-oxides.

Publication ,  Journal Article
Johnson, KE; Rajagopalan, KV
Published in: J Biol Chem
April 20, 2001

Dimethyl sulfoxide reductase (DMSOR), trimethylamine-N-oxide reductase (TMAOR), and biotin sulfoxide reductase (BSOR) are members of a class of bacterial oxotransferases that contain the bis(molybdopterin guanine dinucleotide)molybdenum cofactor. The presence of a Tyr residue in the active site of DMSOR and BSOR that is missing in TMAOR has been implicated in the inability of TMAOR, unlike DMSOR and BSOR, to utilize S-oxides. To test this hypothesis, Escherichia coli TMAOR was cloned and expressed at high levels, and site-directed mutagenesis was utilized to generate the Tyr-114 --> Ala and Phe variants of Rhodobacter sphaeroides DMSOR and insert a Tyr residue into the equivalent position in TMAOR. Although all of the mutants turn over in a manner similar to their respective wild-type enzymes, mutation of Tyr-114 in DMSOR results in a decreased specificity for S-oxides and an increased specificity for trimethylamine-N-oxide (Me(3)NO), with a greater change observed for DMSOR-Y114A. Insertion of a Tyr into TMAOR results in a decreased preference for Me(3)NO relative to dimethyl sulfoxide. Kinetic analysis and UV-visible absorption spectra indicate that the ability of DMSOR to be reduced by dimethyl sulfide is lost upon mutation of Tyr-114 and that TMAOR does not exhibit this activity even in the Tyr insertion mutant.

Duke Scholars

Published In

J Biol Chem

DOI

ISSN

0021-9258

Publication Date

April 20, 2001

Volume

276

Issue

16

Start / End Page

13178 / 13185

Location

United States

Related Subject Headings

  • Tyrosine
  • Spectrophotometry
  • Sequence Homology, Amino Acid
  • Sequence Alignment
  • Rhodobacter sphaeroides
  • Recombinant Proteins
  • Pteridines
  • Protein Conformation
  • Oxidoreductases
  • Oxides
 

Citation

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Johnson, K. E., & Rajagopalan, K. V. (2001). An active site tyrosine influences the ability of the dimethyl sulfoxide reductase family of molybdopterin enzymes to reduce S-oxides. J Biol Chem, 276(16), 13178–13185. https://doi.org/10.1074/jbc.M010965200
Johnson, K. E., and K. V. Rajagopalan. “An active site tyrosine influences the ability of the dimethyl sulfoxide reductase family of molybdopterin enzymes to reduce S-oxides.J Biol Chem 276, no. 16 (April 20, 2001): 13178–85. https://doi.org/10.1074/jbc.M010965200.
Johnson, K. E., and K. V. Rajagopalan. “An active site tyrosine influences the ability of the dimethyl sulfoxide reductase family of molybdopterin enzymes to reduce S-oxides.J Biol Chem, vol. 276, no. 16, Apr. 2001, pp. 13178–85. Pubmed, doi:10.1074/jbc.M010965200.

Published In

J Biol Chem

DOI

ISSN

0021-9258

Publication Date

April 20, 2001

Volume

276

Issue

16

Start / End Page

13178 / 13185

Location

United States

Related Subject Headings

  • Tyrosine
  • Spectrophotometry
  • Sequence Homology, Amino Acid
  • Sequence Alignment
  • Rhodobacter sphaeroides
  • Recombinant Proteins
  • Pteridines
  • Protein Conformation
  • Oxidoreductases
  • Oxides