Re-design of Rhodobacter sphaeroides dimethyl sulfoxide reductase. Enhancement of adenosine N1-oxide reductase activity.

Published

Journal Article

The periplasmic DMSO reductase from Rhodobacter sphaeroides f. sp. denitrificans has been expressed in Escherichia coli BL21(DE3) cells in its mature form and with the R. sphaeroides or E. coli N-terminal signal sequence. Whereas the R. sphaeroides signal sequence prevents formation of active enzyme, addition of a 6x His-tag at the N terminus of the mature peptide maximizes production of active enzyme and allows for affinity purification. The recombinant protein contains 1.7-1.9 guanines and greater than 0.7 molybdenum atoms per molecule and has a DMSO reductase activity of 3.4-3.7 units/nmol molybdenum, compared with 3.7 units/nmol molybdenum for enzyme purified from R. sphaeroides. The recombinant enzyme differs from the native enzyme in its color and spectrum but is indistinguishable from the native protein after redox cycling with reduced methyl viologen and Me2SO. Substitution of Cys for the molybdenum-ligating Ser-147 produced a protein with DMSO reductase activity of 1.4-1.5 units/nmol molybdenum. The mutant protein differs from wild type in its color and absorption spectrum in both the oxidized and reduced states. This substitution leads to losses of 61-99% of activity toward five substrates, but the adenosine N1-oxide reductase activity increases by over 400%.

Full Text

Duke Authors

Cited Authors

  • Hilton, JC; Temple, CA; Rajagopalan, KV

Published Date

  • March 26, 1999

Published In

Volume / Issue

  • 274 / 13

Start / End Page

  • 8428 - 8436

PubMed ID

  • 10085074

Pubmed Central ID

  • 10085074

International Standard Serial Number (ISSN)

  • 0021-9258

Digital Object Identifier (DOI)

  • 10.1074/jbc.274.13.8428

Language

  • eng

Conference Location

  • United States