Pseudomonase sp. DJ77에서 Glutathione S-transferase를 암호하는 phnC유전자의 염기서열과 상동성 분석

Abstract

The nucleotide sequence of the structural gene (phnC) encoding a glutathione S-transferase (phnC) was determined. An open reading frame of 603 base pairs, a Shine-Dalgarno sequence upstream from an inititaion codon and a transeriptional lerminator sequence downstream from a stop codon were found. The open reading frame encoded 201 amino acids and calculated molecular weight of the encoded protem was 21,416 Da, which was conpatible with the relative molecular mass by SDS-PAGE. The deduced amino acid sequence of the PhnC protein showed 53.7% and 49% identity with GSTs of Burkholderia cepacia LB400 and Cycloclasticus oligotrophus RB1 respectively. PhnC is cvolutionarily related with the theta class cytosolic GSTs based upon catalytic invariant residues and homology in the primary structure. Although the homologies of the PhnC with alpha, mu, pi, sigma class GSTs were lower than with theta class GSTs, many of the residues assigned to be important for the catalytic mechanism or the structure in cytosolic GSTs were found to be conserved in the PhnC enzyme. In addition, homology GST gene location among P.psedomonas sp.DJ77, B. cepacia LB400, P.peudoalcaligenes KF707 and C.oligotrophus RB1 suggests that the PhnC GST might be involved in degradation of aromatic hydrocarbons.