The iscS gene is essential for the biosynthesis of 2-selenouridine in tRNA and the selenocysteine-containing formate dehydrogenase H.
Proc Natl Acad Sci U S A
; 99(10): 6679-83, 2002 May 14.
Article
em En
| MEDLINE
| ID: mdl-11997471
ABSTRACT
Three NifS-like proteins, IscS, CSD, and CsdB, from Escherichia coli catalyze the removal of sulfur and selenium from L-cysteine and L-selenocysteine, respectively, to form L-alanine. These enzymes are proposed to function as sulfur-delivery proteins for iron-sulfur cluster, thiamin, 4-thiouridine, biotin, and molybdopterin. Recently, it was reported that selenium mobilized from free selenocysteine is incorporated specifically into a selenoprotein and tRNA in vivo, supporting the involvement of the NifS-like proteins in selenium metabolism. We here report evidence that a strain lacking IscS is incapable of synthesizing 5-methylaminomethyl-2-selenouridine and its precursor 5-methylaminomethyl-2-thiouridine (mnm(5)s(2)U) in tRNA, suggesting that the sulfur atom released from L-cysteine by the action of IscS is incorporated into mnm(5)s(2)U. In contrast, neither CSD nor CsdB was essential for production of mnm(5)s(2)U and 5-methylaminomethyl-2-selenouridine. The lack of IscS also caused a significant loss of the selenium-containing polypeptide of formate dehydrogenase H. Together, these results suggest a dual function of IscS in sulfur and selenium metabolism.
Texto completo:
1
Coleções:
01-internacional
Contexto em Saúde:
3_ND
Base de dados:
MEDLINE
Assunto principal:
Liases de Carbono-Enxofre
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Tiouridina
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Uridina
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RNA de Transferência
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Selenocisteína
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Escherichia coli
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Formiato Desidrogenases
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Hidrogenase
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Complexos Multienzimáticos
Idioma:
En
Revista:
Proc Natl Acad Sci U S A
Ano de publicação:
2002
Tipo de documento:
Article