title: Cloning and characterization of the gene encoding glutamate 1-semialdehyde 2,1-aminomutase, which is involved in delta-aminolevulinic acid synthesis in Propionibacterium freudenreichii.
abstract: The gene from Propionibacterium freudenreichii that encodes glutamate 1-semialdehyde 2,1-aminomutase (EC 5.4.3.8), which is involved in the C5 pathway for synthesis of delta-aminolevulinic acid (ALA), a precursor in heme and cobalamin biosynthesis, was cloned onto a multicopy plasmid, pUC18, via complementation of an ALA-deficient mutant (hemL) of Escherichia coli. Subcloning of fragments from the initial 3.3-kb chromosomal fragment allowed the isolation of a 1.9-kb fragment which could complement the hemL mutation. Nucleotide sequence analysis of the 1.9-kb DNA fragment revealed an open reading frame (ORF) that was located downstream from a potential ribosome-binding site. The ORF encoded a polypeptide of 441 amino acid residues, and the deduced molecular mass of this polypeptide is 45,932 Da. A high G+C content (70 mol%) of the codons of the ORF was found and was consistent with the taxonomic features of Propionibacterium species. The amino acid sequence showed a high degree of homology with those of the HemL proteins from other organisms, and a putative binding site for pyridoxal 5'-phosphate was conserved, with the exception of a single substitution of phenylalanine for leucine. These results suggest that ALA is synthesized via the C5 pathway in a producer of vitamin B12, P. freudenreichii.
authors.affiliation: Department of Fermentation Technology, Faculty of Engineering, Hiroshima University, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Murakami
authors.forename: Y
authors.initials: Y
authors.lastname: Hashimoto
authors.forename: Y
authors.initials: Y
authors.lastname: Murooka
mesh_terms: D000595:Amino Acid Sequence; D000622:Aminolevulinic Acid / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics* / Q000302:isolation & purification; D001483:Base Sequence; D003001:Cloning, Molecular; D005798:Genes, Bacterial; D019751:Intramolecular Transferases; D007535:Isomerases / Q000235:genetics* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D011424:Propionibacterium / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D000622:Aminolevulinic Acid; D007535:Isomerases; D019751:Intramolecular Transferases; C061049:glutamate-1-semialdehyde 2,1-aminomutase