title: Cloning, sequencing and expression of the L-2-hydroxyisocaproate dehydrogenase-encoding gene of Lactobacillus confusus in Escherichia coli.
abstract: The gene (L-HicDH) encoding L-2-hydroxyisocaproate dehydrogenase (L-HicDH) from Lactobacillus confusus was cloned in Escherichia coli. A 69-mer oligodeoxyribonucleotide probe, derived to be complementary to the N-terminal amino acid (aa) coding sequence, was used for screening. The complete nucleotide (nt) sequence of the L-HicDH gene was determined. The 5'-end of the mRNA was mapped by primer extension and the promoter identified. Downstream from the L-HicDH gene is a typical Rho-independent terminator. The aa sequence of L-HicDH, deduced from the nt sequence, has an overall similarity of 30% to the aa sequence of L-lactate dehydrogenase (L-LDH) from Lactobacillus casei. The aa residues involved in binding of coenzyme and substrate are highly conserved in L-HicDH with respect to prokaryotic and eukaryotic L-LDHs. The L-HicDH gene could be expressed under control of phage lambda 'Leftward' and 'rightward' promoters in E. coli up to 35% of total cell protein. The enzyme produced under these conditions exhibits full specific activity and is found exclusively in soluble form.
authors.affiliation: Gesellschaft für Biotechnologische Forschung mbH, Braunschweig, F.R.G.
authors.forename: H P
authors.initials: HP
authors.lastname: Lerch
authors.forename: R
authors.initials: R
authors.lastname: Frank
authors.forename: J
authors.initials: J
authors.lastname: Collins
mesh_terms: D000429:Alcohol Oxidoreductases / Q000235:genetics*; D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D003062:Codon / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics*; D015870:Gene Expression; D005798:Genes, Bacterial; D007778:Lactobacillus / Q000201:enzymology / Q000235:genetics*; D008969:Molecular Sequence Data; D010957:Plasmids; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D013728:Terminator Regions, Genetic
chemical_list: D003062:Codon; D000429:Alcohol Oxidoreductases; C047961:2-hydroxyisocaproate dehydrogenase