Analysis of the C-terminal domain of Burkholderia sp. strain LB400 BphK reveals a conserved motif that affects catalytic activity

Authors

  • Niamh Gilmartin,

    Search for more papers by this author
    • 1

      Laboratoire de Dynamique, Evolution et Expression de Genomes de Microorganismes, FRE2326, Universite Louis Pasteur, 28 Rue Goethe, 67083 Strasbourg, France.

  • David Ryan,

    1. Department of Science and Health, School of Science, Institute of Technology Carlow, Kilkenny Road, Carlow, Ireland
    Search for more papers by this author
  • David N. Dowling

    Corresponding author
    1. Department of Science and Health, School of Science, Institute of Technology Carlow, Kilkenny Road, Carlow, Ireland
    Search for more papers by this author

  • Edited by W.J. Mitchell

*Corresponding author. Tel.: +353 59 9170479; fax: +353 59 9170517., E-mail address: dowlingd@itcarlow.ie

Abstract

The bphK gene encoding glutathione S-transferase (GST) is located in the bph operon (PCB co-metabolism) in Burkholderia sp. strain LB400 and the enzyme has recently been shown to have dechlorination activity in relation to 4-chlorobenzoate (4-CBA). Alignments using other glutathione S-transferase sequences found in PCB degradation operons identified a highly conserved region in the C-terminal domain of these enzymes that included a conserved motif implicated in protein folding in eukaryotic GSTs. Site-directed mutagenesis indicated that the region is indirectly involved in the catalytic activity and substrate specificity of BphK. Predicted hydrogen bond interactions involving Asp155 play an important role in the enzymatic properties of this glutathione S-transferase.

Ancillary