title: Cloning and sequence analysis of the meso-diaminopimelate decarboxylase gene from Bacillus methanolicus MGA3 and comparison to other decarboxylase genes.
abstract: The lysA gene of Bacillus methanolicus MGA3 was cloned by complementation of an auxotrophic Escherichia coli lysA22 mutant with a genomic library of B. methanolicus MGA3 chromosomal DNA. Subcloning localized the B. methanolicus MGA3 lysA gene into a 2.3-kb SmaI-SstI fragment. Sequence analysis of the 2.3-kb fragment indicated an open reading frame encoding a protein of 48,223 Da, which was similar to the meso-diaminopimelate (DAP) decarboxylase amino acid sequences of Bacillus subtilis (62%) and Corynebacterium glutamicum (40%). Amino acid sequence analysis indicated several regions of conservation among bacterial DAP decarboxylases, eukaryotic ornithine decarboxylases, and arginine decarboxylases, suggesting a common structural arrangement for positioning of substrate and the cofactor pyridoxal 5'-phosphate. The B. methanolicus MGA3 DAP decarboxylase was shown to be a dimer (M(r) 86,000) with a subunit molecular mass of approximately 50,000 Da. This decarboxylase is inhibited by lysine (Ki = 0.93 mM) with a Km of 0.8 mM for DAP. The inhibition pattern suggests that the activity of this enzyme in lysine-overproducing strains of B. methanolicus MGA3 may limit lysine synthesis.
authors.affiliation: Department of Biochemistry, University of Minnesota, St. Paul 55108.
authors.forename: D A
authors.initials: DA
authors.lastname: Mills
authors.forename: M C
authors.initials: MC
authors.lastname: Flickinger
mesh_terms: D000595:Amino Acid Sequence; D001407:Bacillus / Q000201:enzymology* / Q000235:genetics*; D001426:Bacterial Proteins; D001483:Base Sequence; D002262:Carboxy-Lyases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics*; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000235:genetics; D005798:Genes, Bacterial; D008239:Lysine / Q000096:biosynthesis; D008969:Molecular Sequence Data; D008970:Molecular Weight; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D002262:Carboxy-Lyases; C079912:LysA protein, Bacteria; C020031:diaminopimelic acid decarboxylase; D008239:Lysine