Molecular and catalytic characterization of a phi class glutathione transferase from Cathaya argyrophylla
2012 (English)In: Biochemical Systematics and Ecology, ISSN 0305-1978, E-ISSN 1873-2925, Vol. 40, 75-85 p.Article in journal (Refereed) Published
Plant phi class glutathione transferases (GSTs) play important roles in stress tolerance and detoxification metabolism. This study reports the cloning, expression and biochemical characteristics of a phi GST gene (CaGSTF) from the endemic and endangered conifer Cathaya argyrophylla. The recombinant CaGSTF showed GSH-conjugating activity towards the substrate NED-Cl and CDNB. Kinetic analysis revealed low catalytic efficiency with a k(cat)/K-m(GSH) value of 9.82 mM(-1)S(-1). The CaGSTF proved to be a thermolabile enzyme, at 40 degrees C the enzyme's activity was nearly abolished. Site-directed mutagenesis revealed that Ser12, Lys42, Ile55, Glu67 and Ser68 of CaGSTF are critical components of glutathione-binding sites that contribute to the enzyme's catalytic activity. Compared to other plant phi GSTs and conifer tau GSTs, CaGSTF showed a narrow substrate spectrum, low catalytic efficiency and thermolability. These atypical properties suggest the enzyme may have a limited functional role in the organism's adaptation to environmental stresses in the subtropical regions. (C) 2011 Elsevier Ltd. All rights reserved.
Place, publisher, year, edition, pages
Oxford: Pergamon Press, 2012. Vol. 40, 75-85 p.
Cathaya argyrophylla, Gymnosperm, Enzyme characterization, Site-directed mutagenesis, Protein structure
Biochemistry and Molecular Biology
IdentifiersURN: urn:nbn:se:umu:diva-54142DOI: 10.1016/j.bse.2011.10.010ISI: 000299712700017OAI: oai:DiVA.org:umu-54142DiVA: diva2:516722