title: Cloning and nucleotide sequence of the thrB gene from the cyanobacterium Calothrix PCC 7601.
abstract: The cyanobacterium Calothrix PCC 7601 thrB gene, encoding homoserine kinase (EC 2.7.1.39), was cloned via complementation of an Escherichia coli threonine auxotroph, and its nucleotide sequence was determined. The comparison of the homoserine kinase amino acid sequences from Calothrix PCC 7601, E. coli K12 and Bacillus subtilis 168 indicates a closer relationship between cyanobacteria and bacillaceae than between cyanobacteria and enterobacteriaceae. Sequence analysis of the 5' and 3' flanking regions of the Calothrix thrB gene revealed the existence of a 169-codon-long open reading frame downstream from thrB: this sequence may be the second gene of a Calothrix thr operon. Two types of tandemly repeated sequences, sharing similarities with other prokaryotic transcriptional regulatory elements, were detected in the region upstream from the thrB gene.
authors.affiliation: Département de Biochimie et Génétique Moléculaire, Institut Pasteur, Paris, France.
authors.forename: C
authors.initials: C
authors.lastname: Parsot
authors.forename: D
authors.initials: D
authors.lastname: Mazel
mesh_terms: D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000201:enzymology / Q000235:genetics; D001483:Base Sequence; D003001:Cloning, Molecular; D000458:Cyanobacteria / Q000201:enzymology / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics; D005796:Genes; D005816:Genetic Complementation Test; D008969:Molecular Sequence Data; D010770:Phosphotransferases / Q000235:genetics*; D017853:Phosphotransferases (Alcohol Group Acceptor); D010957:Plasmids; D012689:Sequence Homology, Nucleic Acid
chemical_list: D010770:Phosphotransferases; D017853:Phosphotransferases (Alcohol Group Acceptor); C021370:homoserine kinase