Implication of two glutathione S-transferases in the optimal metabolism of m-toluate by Sphingomonas yanoikuyae B1.
A putative glutathione S-transferase (GST) gene (bphK) was identified in the meta-cleavage operon for the degradation of m-toluate by Sphingomonas yanoikuyae B1. Disruption of bphK resulted in the loss of GST activity against 1-chloro-2,4-dinitrobenzene and a much increased lag time of the mutant strain MB3 (bphK::Km) following subculture into m-toluate medium. In contrast, an increased lag time was not observed when MB3 was grown on biphenyl or m-xylene and MB3 showed normal growth on m-toluate when complemented with a subclone containing the bphK gene only. Furthermore, an additional GST activity was detected in MB3. The induction timing of this second GST activity coincided with the beginning of the exponential growth phase of MB3 on m-toluate, reached maximal activity within three hours, and then dropped sharply to the basal level. Thus, it is apparent that BphK and/or the second GST are necessary for optimal growth of B1 on m-toluate.
Bae
Mihyun
M
Department of Biology, Institute of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea.
Sul
Woo Jun
WJ
Koh
Sung-Cheol
SC
Lee
Joon H
JH
Zylstra
Gerben J
GJ
Kim
Young Min
YM
Kimr
Eungbin
E
D001565:Benzoates / Q000378:metabolism*; D005982:Glutathione Transferase / Q000235:genetics / Q000378:metabolism*; D006841:Hydrocarbons, Aromatic / Q000378:metabolism; D009876:Operon; D020578:Sphingomonas / Q000201:enzymology* / Q000235:genetics
D001565:Benzoates; D006841:Hydrocarbons, Aromatic; C009503:3-toluic acid; D005982:Glutathione Transferase