title: Discovery of a functional polymorphism in human glutathione transferase zeta by expressed sequence tag database analysis.
abstract: Analysis of the expressed sequence tag (EST) database by sequence alignment allows a rapid screen for polymorphisms in proteins of physiological interest. The human zeta class glutathione transferase GSTZ1 has recently been characterized and analysis of expressed sequence tag clones suggested that this gene may be polymorphic. This report identifies three GSTZ1 alleles resulting from A to G transitions at nucleotides 94 and 124 of the coding region, GSTZ1*A-A94A124; GSTZ1*B-A94G124; GSTZ1*C-G94G124. Polymerase chain reaction/restriction fragment length polymorphism analysis of a control Caucasian population (n = 141) showed that all three alleles were present, with frequencies of 0.09, 0.28 and 0.63 for Z1*A, Z1*B and Z1*C, respectively. These nucleotide substitutions are non-synonymous, with A to G at positions 94 and 124 encoding Lys32 to Glu and Arg42 to Gly substitutions, respectively. The variant proteins were expressed in Escherichia coli as 6X His-tagged proteins and purified by Ni-agarose column chromatography. Examination of the activities of recombinant proteins revealed that GSTZ1a-1a displayed differences in activity towards several substrates compared with GSTZ1b-1b and GSTZ1c-1c, including 3.6-fold higher activity towards dichloroacetate. This report demonstrates the discovery of a functional polymorphism by analysis of the EST database.
authors.affiliation: Division of Molecular Medicine, John Curtin School of Medical Research Australian National University, Canberra, ACT.
authors.forename: A C
authors.initials: AC
authors.lastname: Blackburn
authors.forename: H F
authors.initials: HF
authors.lastname: Tzeng
authors.forename: M W
authors.initials: MW
authors.lastname: Anders
authors.forename: P G
authors.initials: PG
authors.lastname: Board
mesh_terms: D000085:Acetates / Q000378:metabolism; D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D001483:Base Sequence; D002846:Chromatography, Affinity; D016208:Databases, Factual; D003999:Dichloroacetic Acid / Q000378:metabolism; D004789:Enzyme Activation / Q000235:genetics; D004791:Enzyme Inhibitors / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D004976:Ethacrynic Acid / Q000378:metabolism; D005091:Exons; D020224:Expressed Sequence Tags; D005260:Female; D005463:Fluoroacetates / Q000378:metabolism; D005787:Gene Frequency; D005982:Glutathione Transferase / Q000235:genetics* / Q000378:metabolism; D006239:Haplotypes; D006801:Humans; D006843:Hydrocarbons, Chlorinated; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D010648:Phenylacetates / Q000378:metabolism; D011110:Polymorphism, Genetic / Q000235:genetics*; D012150:Polymorphism, Restriction Fragment Length; D011422:Propionates / Q000378:metabolism; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: D000085:Acetates; D004791:Enzyme Inhibitors; D005463:Fluoroacetates; D006843:Hydrocarbons, Chlorinated; D007527:Isoenzymes; D010648:Phenylacetates; D011422:Propionates; D011993:Recombinant Fusion Proteins; C120963:chlorofluoroacetic acid; D003999:Dichloroacetic Acid; C021974:2-chloropropionic acid; C014815:fluoroacetic acid; C407705:GSTZ1 protein, human; C498692:Gstz1 protein, rat; D005982:Glutathione Transferase; C118008:4-nitrophenylacetic acid; D004976:Ethacrynic Acid