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Titolo:
Rat glutathione S-transferase M4-4: an isoenzyme with unique structural features including a redox-reactive cysteine-115 residue that forms mixed disulphides with glutathione
Autore:
Cheng, H; Tchaikovskaya, T; Tu, YSL; Chapman, J; Qian, B; Ching, WM; Tien, M; Rowe, JD; Patskovsky, YV; Listowsky, I; Tu, CPD;
Indirizzi:
Penn State Univ, Dept Biochem & Mol Biol, University Pk, PA 16802 USA PennState Univ University Pk PA USA 16802 l, University Pk, PA 16802 USA Yeshiva Univ Albert Einstein Coll Med, Dept Biochem, Bronx, NY 10461 USA Yeshiva Univ Albert Einstein Coll Med Bronx NY USA 10461 nx, NY 10461 USA USN, Med Res Ctr, Viral & Rickettsial Dis Dept, Infect Dis Directorate, Bethesda, MD 20889 USA USN Bethesda MD USA 20889 Infect Dis Directorate, Bethesda, MD 20889 USA
Titolo Testata:
BIOCHEMICAL JOURNAL
, volume: 356, anno: 2001,
parte:, 2
pagine: 403 - 414
SICI:
0264-6021(20010601)356:<403:RGSMAI>2.0.ZU;2-C
Fonte:
ISI
Lingua:
ENG
Soggetto:
CATALYTIC MECHANISM; ESCHERICHIA-COLI; BUTYLATED HYDROXYANISOLE; CRYSTAL-STRUCTURE; SUPERGENE FAMILY; YB SUBUNIT; EXPRESSION; GENE; IDENTIFICATION; LIVER;
Keywords:
glutathiolation; mass spectrometry; oxidative stress; structural model; synthetic gene;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
44
Recensione:
Indirizzi per estratti:
Indirizzo: Tu, CPD Penn State Univ, Dept Biochem & Mol Biol, University Pk, PA 16802 USA Penn State Univ University Pk PA USA 16802 rsity Pk, PA 16802 USA
Citazione:
H. Cheng et al., "Rat glutathione S-transferase M4-4: an isoenzyme with unique structural features including a redox-reactive cysteine-115 residue that forms mixed disulphides with glutathione", BIOCHEM J, 356, 2001, pp. 403-414

Abstract

Although the existence of the rat glutathione S-transferase (GST) M4 (rGSTM4) gene has been known for some time, the corresponding protein has not asyet been purified from tissue. A recombinant rCSTM4-4 was;thus expressed in Escherichia coli from a chemically synthesized rGSTM4 gene. The catalyticefficiency (k(cat)/K-m) of rGSTM4-4 for the 1-chloro-2,4-dinitro-benzene (CDNB) conjugation reaction was 50-180-fold less than that of the well-characterized homologous rGSTM1-1, and the pH optimum for the same reaction was 8.5 for rGSTM4-4 as opposed to 6.5 for rGSTM1-1. Molecular-modelling studies predict that key substitutions in the helix alpha4 region of rGSTM4-4 account for this pK(a) difference. A notable structural feature of rGSTM4-4 isthe Cys-115 residue in place of the Tyr-115 of other Mu-class GSTs. The thiol group of Cys-115 is redox-reactive and readily forms a mixed disulphideeven with GSH; the S-glutathiolated form of the enzyme is catalytically active. A mutated rGSTM4-4 (C115Y) had 6-10-fold greater catalytic efficiencythan the wild-type rGSTM4-4. Trp-45, a conserved residue among Mu-class GSTs, is essential in rGSTM4-4 for both enzyme activity and binding to glutathione affinity matrices. Antibodies directed against either the unique C-terminal undecapeptide or tridecapeptide of rGSTM4 reacted with rat and mouseliver GSTs to reveal an orthologous mouse GSTM4-4 present at low basal levels but which is inducible in mouse liver. This subclass of rodent Mu GSTs with redox-active Cys-115 residues could have specialized physiological functions in response to oxidative stress.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 07/08/20 alle ore 07:01:34