|
type |
Journal Article |
authors |
Forchhammer, K.; Leinfelder, W.; Boesmiller, K.; Veprek, B.; Bock, A. |
title |
Selenocysteine synthase from Escherichia coli. Nucleotide sequence of the gene (selA) and purification of the protein |
journal |
J Biol Chem |
Activity |
2.9.1.1 |
Family |
2.9.1.1 |
sel |
selected |
ui |
2007584 |
year |
(1991) |
volume |
266 |
number |
10 |
pages |
6318-23 |
| |
keywords |
Amino Acid Sequence |
abstract |
The nucleotide sequence of the selA gene from Escherichia coli whose product is involved in the conversion of seryl-tRNA(Sec UCA) into selenocysteyl-tRNA(Sec UCA) was determined. selA codes for a polypeptide of a calculated Mr of 50,667; a protein of appropriate size was synthesized in vivo in a T7 promoter/polymerase system. An assay for SELA activity was devised which is based on the seryl-tRNA(Sec UCA)- dependent incorporation of [75Se] selenium into acid-insoluble material. It was used to follow SELA purification from cells that overproduced the protein from a phage T7 promoter plasmid. Purified native SELA protein migrates in gel filtration experiments with a native Mr of about 600,000. SELA contains 1 mol of bound pyridoxal 5- phosphate/mol of 50-kDa subunit. Evidence is presented that the overall conversion of seryl-tRNA(Sec UCA) to selenocysteyl-tRNA(Sec UCA) occurs at the SELA protein. SELA, therefore, has the function of a selenocysteine synthase. |
last changed |
2009/05/20 16:31 |
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