1887

Abstract

Summary: The aspartokinase II () operon of consists of two in-phase overlapping genes that encode the two subunits of the lysine-sensitive isoenzyme of aspartokinase (ATP:-aspartate 4-phosphotransferase, EC 2.7.2.4). Transduction mapping of the operon, inactivated by recombinational insertion of a marker, indicates a chromosomal location (about 253°) between and is thus remote from , eliminating as a possible locus for the structural gene of aspartokinase II, but close to and The nucleotide sequence of a 2 kb DNA fragment just upstream of the operon was determined and found to contain two open reading frames. The deduced amino acid sequence of the distal reading frame exhibits extensive homology with thioredoxin and that of the proximal one, which overlaps with the promoter, is homologous to the deduced product of the gene. Insertional mutagenesis of the proximal open reading frame led to a mitomycin-sensitive phenotype, consistent with a role in DNA repair. In conjunction with the data of M. Petricek, L. Rutberg & L. Hederstedt [ 61, 85-88] our results define the nucleotide sequence of an 8·8 kb segment of the chromosome near 253° and the following order of genes: -orfX--orfY-.

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/content/journal/micro/10.1099/00221287-135-11-2931
1989-11-01
2019-10-18
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http://instance.metastore.ingenta.com/content/journal/micro/10.1099/00221287-135-11-2931
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