title: Organization of genes for tetrapyrrole biosynthesis in gram--positive bacteria.
abstract: Clusters of genes encoding enzymes for tetrapyrrole biosynthesis were cloned from Bacillus sphaericus, Bacillus stearothermophilus, Brevibacillus brevis and Paenibacillus macerans. The sequences of all hemX genes found, and of a 6.3 kbp hem gene cluster from P. macerans, were determined. The structure of the hem gene clusters was compared to that of other Gram-positive bacteria. The Bacillus and Brevibacillus species have a conserved organization of the genes hemAXCDBL, required for biosynthesis of uroporphyrinogen III (UroIII) from glutamyl-tRNA. In P. macerans, the hem genes for UroIII synthesis are also closely linked but their organization is different: there is no hemX gene and the gene cluster also contains genes, cysG8 and cysG(A)-hemD, encoding the enzymes required for synthesis of sirohaem from UroIII. Bacillus subtilis contains genes for three proteins, NasF, YInD and YInF, with sequence similarity to Escherichia coli CysG, which is a multi-functional protein catalysing sirohaem synthesis from UroIII. It is shown that YInF is required for sirohaem synthesis and probably catalyses the precorrin-2 to sirohaem conversion. YInD probably catalyses precorrin-2 synthesis from UroIII and NasF seems to be specific for nitrite reduction.
authors.forename: Per
authors.initials: P
authors.lastname: Johansson
authors.forename: Lars
authors.initials: L
authors.lastname: Hederstedt
mesh_terms: D000595:Amino Acid Sequence; D001406:Bacillaceae / Q000235:genetics*; D001407:Bacillus / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics*; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D006094:Gram-Positive Bacteria / Q000235:genetics*; D006418:Heme / Q000031:analogs & derivatives / Q000096:biosynthesis; D008780:Methyltransferases / Q000235:genetics; D008969:Molecular Sequence Data; D005810:Multigene Family; D011758:Pyrroles / Q000378:metabolism*; D012346:RNA, Transfer, Amino Acyl / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D045725:Tetrapyrroles; D014577:Uroporphyrinogens / Q000096:biosynthesis; D014578:Uroporphyrins / Q000096:biosynthesis
chemical_list: D001426:Bacterial Proteins; D011758:Pyrroles; D012346:RNA, Transfer, Amino Acyl; D045725:Tetrapyrroles; D014577:Uroporphyrinogens; D014578:Uroporphyrins; D006418:Heme; C009272:siroheme; C063209:15,23-dihydrosirohydrochlorin; D008780:Methyltransferases; C058315:HemX protein, Bacteria; C060508:uroporphyrin-III C-methyltransferase