title: Sulfation of hydroxychlorobiphenyls. Molecular cloning, expression, and functional characterization of zebrafish SULT1 sulfotransferases.
abstract: As a first step toward developing a zebrafish model for investigating the role of sulfation in counteracting environmental estrogenic chemicals, we have embarked on the identification and characterization of cytosolic sulfotransferases (STs) in zebrafish. By searching the zebrafish expressed sequence tag database, we have identified two cDNA clones encoding putative cytosolic STs. These two zebrafish ST cDNAs were isolated and subjected to nucleotide sequencing. Sequence data revealed that the two zebrafish STs are highly homologous, being approximately 82% identical in their amino acid sequences. Both of them display approximately 50% amino acid sequence identity to human SULT1A1, rat SULT1A1, and mouse SULT1C1 ST. These two zebrafish STs therefore appear to belong to the SULT1 cytosolic ST gene family. Recombinant zebrafish STs (designated SULT1 STs 1 and 2), expressed using the pGEX-2TK prokaryotic expression system and purified from transformed Escherichia coli cells, migrated as approximately 35 kDa proteins on SDS/PAGE. Purified zebrafish SULT1 STs 1 and 2 displayed differential sulfating activities toward a number of endogenous compounds and xenobiotics including hydroxychlorobiphenyls. Kinetic constants of the two enzymes toward two representative hydroxychlorobiphenyls, 3-chloro-4-biphenylol and 3,3',5,5'-tetrachloro-4,4'-biphenyldiol, and 3,3',5-triiodo-l-thyronine were determined. A thermostability experiment revealed the two enzymes to be relatively stable over the range 20-43 degrees C. Among 10 different divalent metal cations tested, Co2+, Zn2+, Cd2+, and Pb2+ exhibited considerable inhibitory effects, while Hg2+ and Cu2+ rendered both enzymes virtually inactive.
authors.affiliation: Biomedical Research Center, The University of Texas Health Center, Tyler, Texas 75708, USA.
authors.forename: Takuya
authors.initials: T
authors.lastname: Sugahara
authors.forename: Chau-Ching
authors.initials: CC
authors.lastname: Liu
authors.forename: T Govind
authors.initials: TG
authors.lastname: Pai
authors.forename: Paul
authors.initials: P
authors.lastname: Collodi
authors.forename: Masahito
authors.initials: M
authors.lastname: Suiko
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Sakakibara
authors.forename: Kazuo
authors.initials: K
authors.lastname: Nishiyama
authors.forename: Ming-Cheh
authors.initials: MC
authors.lastname: Liu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015239:Arylsulfotransferase; D001713:Biphenyl Compounds / Q000378:metabolism*; D015153:Blotting, Western; D002412:Cations; D003001:Cloning, Molecular; D003600:Cytosol / Q000378:metabolism; D017931:DNA Primers / Q000737:chemistry; D018076:DNA, Complementary / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D015238:Sulfotransferases / Q000737:chemistry / Q000378:metabolism*; D013696:Temperature; D015027:Zebrafish
chemical_list: D001713:Biphenyl Compounds; D002412:Cations; D017931:DNA Primers; D018076:DNA, Complementary; D011994:Recombinant Proteins; D015238:Sulfotransferases; D015239:Arylsulfotransferase; C117544:SULT1A1 protein, human; C513291:Sult1a1 protein, mouse; C513288:Sult1c1 protein, mouse