Overexpression of arylsulfate sulfotransferase as fusion protein with glutathione S-transferase

Molecular cloning of the arylsulfate sulfotransferase gene and characterization of its product from Enterobacter amnigenus AR-37

The gene encoding the Enterobacter amnigenus AR-37 arylsulfate sulfotransferase (ASST) was cloned, sequenced, and expressed in Escherichia coli NM522. Sequencing led to the identification of three contiguous open reading frames (ORFs) on the same strand. Based on amino acid sequence homology, ORF1, ORF2, and ORF3 are designated astA, dsbA, and dsbB, respectively. A multiple sequence alignment revealed conserved regions in ASST. An N-terminal amino acid sequence analysis of the purified ASST from E. coli NM522 (pEAST72) showed that it is subject to N-terminal processing. The specific activity of purified ASST is 436.5 U/mg of protein. The enzyme is a monomeric protein with a molecular mass of 64 kDa. Using phenol as an acceptor substrate, 4-methylumbelliferyl sulfate is the best donor substrate, followed by beta-naphthyl sulfate, p-nitrophenyl sulfate (PNS), and alpha-naphthyl sulfate. For PNS, alpha-naphthol is the best acceptor substrate, followed by phenol, resorcinol, p-acetaminophen, tyramine, and tyrosine. The enzyme has a different acceptor specificity than the enzyme purified from Eubacterium A-44. It is similar to Klebsiella K-36 and Haemophilus K-12. The apparent K(m) values for PNS using phenol as an acceptor and for phenol using PNS as a donor are 0.163 and 0.314 mM, respectively. The pI and optimum pH are 6.1 and 9.0, respectively.

Distribution of bacteria with the arylsulfate sulfotransferase activity

This study is to predict the possible roles of the arylsulfate sulfotransferase (ASST) in the microorganism. At first we studied the spectrum of a distribution of the ASST enzyme through about 1,300 bacteria and the several selected strains were compared with Klebsiella K-36 previously reported in the level of DNA homology using the Southern blot method. From this study, we could predict that this enzyme would not exist in specific bacteria and it might not be a critical enzyme for the life of bacteria.