In vitro synthesis of selenocysteinyl-tRNA(UCA) from seryl-tRNA(UCA): involvement and characterization of the selD gene product.
Proc Natl Acad Sci U S A
; 87(2): 543-7, 1990 Jan.
Article
em En
| MEDLINE
| ID: mdl-2405383
ABSTRACT
The selD gene from Escherichia coli, whose product is involved in selenium metabolism, has been cloned and sequenced. selD codes for a protein of 347 amino acids with a calculated molecular weight of 36,687. Analysis of the selD gene product through expression of the gene in the phage T7 promoter/polymerase system confirmed the predicted molecular weight of the protein. Gene disruption experiments demonstrated that the SelD protein is required both for the incorporation of selenium into the modified nucleoside 5-methylaminomethyl-2-selenouridine of tRNA and for the biosynthesis of selenocysteine from an L-serine residue esterbonded to tRNA(Ser)(UCA). tRNA(Ser)(UCA) has been purified, aminoacylated with L-serine, and used as a substrate for the development of an in vitro system for selenocysteine biosynthesis. Efficient formation of selenocysteinyl-tRNA(Ser)(UCA) was achieved by using extracts in which both the selD and the selA gene products were overproduced. The results demonstrate that selenocysteine is synthesized from L-serine bound to tRNA(UCA) and they are in accord with SelD functioning as a donor of reduced selenium.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Fosfotransferases
/
Proteínas de Bactérias
/
RNA de Transferência Aminoácido-Específico
/
RNA de Transferência de Serina
/
Aminoacil-RNA de Transferência
/
Proteínas de Drosophila
/
Escherichia coli
/
Genes Bacterianos
Idioma:
En
Revista:
Proc Natl Acad Sci U S A
Ano de publicação:
1990
Tipo de documento:
Article