type	Journal Article
authors	Zinoni, F.; Birkmann, A.; Stadtman, T. C.; Bock, A.
title	Nucleotide sequence and expression of the selenocysteine-containing polypeptide of formate dehydrogenase (formate-hydrogen-lyase-linked) from Escherichia coli
journal	Proc Natl Acad Sci U S A
Activity	4.4.1.16
ui	86259655
year	(1986)
volume	83
number	13
pages	4650-4.
keywords	Aldehyde Oxidoreductases/*genetics
abstract	The gene (fdhF) coding for the selenopolypeptide of the benzylviologen- linked formate dehydrogenase of Escherichia coli was cloned and its nucleotide sequence was determined. The fdhF gene contains, within an open reading frame coding for a protein of 715 amino acids (calculated molecular weight, 79,087), an opal (UGA) nonsense codon in amino acid position 140. Existence of this nonsense codon was confirmed by physical recloning and resequencing. Internal and terminal deletion clones and lacZ fusions of different N-terminal parts of fdhF were constructed and analyzed for selenium incorporation. Selenylated truncated polypeptide chains or beta-galactosidase fusion proteins were synthesized when the deletion clones or gene fusions, respectively, contained the fdhF gene fragment coding for the selenopolypeptide sequence from amino acid residue 129 to amino acid residue 268. Translation of the lacZ part of the fusions required the presence of selenium in the medium when the N-terminal fdhF part contained the UGA codon and was independent of the presence of selenium when a more upstream part of fdhF was fused to lacZ. The results are consistent with a co-translational selenocysteine incorporation mechanism.
last changed	2002/11/12 16:17