title: Heme protein and hydroxyarginase necessary for biosynthesis of D-cycloserine.
abstract: We have recently cloned a D-cycloserine (DCS) biosynthetic gene cluster that consists of 10 genes, designated dcsA~dcsJ, from Streptomyces lavendulae ATCC 11924 (16). In the predicted pathway of hydroxyurea (HU) formation in DCS biosynthesis, L-arginine (L-Arg) must first be hydroxylated, prior to the hydrolysis of N(ω)-hydroxy-L-arginine (NHA) by DcsB, an arginase homolog. The hydroxylation of L-Arg is known to be catalyzed by nitric oxide synthase (NOS). In this study, to verify the supply route of HU, we created a dcsB-disrupted mutant, ΔdcsB. While the mutant lost DCS productivity, its productivity was restored by complementation of dcsB, and also by the addition of HU but not NHA, suggesting that HU is supplied by DcsB. A NOS-encoding gene, nos, from S. lavendulae chromosome was cloned, to create a nos-disrupted mutant. However, the mutant maintained the DCS productivity, suggesting that NOS is not necessary for DCS biosynthesis. To clarify the identity of an enzyme necessary for NHA formation, a dcsA-disrupted mutant, designated ΔdcsA, was also created. The mutant lost DCS productivity, whereas the DCS productivity was restored by complementation of dcsA. The addition of NHA to the culture medium of ΔdcsA mutant was also effective to restore DCS production. These results indicate that the dcsA gene product, DcsA, is an enzyme essential to generate NHA as a precursor in the DCS biosynthetic pathway. Spectroscopic analyses of the recombinant DcsA revealed that it is a heme protein, supporting an idea that DcsA is an enzyme catalyzing hydroxylation.
authors.affiliation: Department of Molecular Microbiology and Biotechnology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan.
authors.forename: Takanori
authors.initials: T
authors.lastname: Kumagai
authors.forename: Kisho
authors.initials: K
authors.lastname: Takagi
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Koyama
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Matoba
authors.forename: Kosuke
authors.initials: K
authors.lastname: Oda
authors.forename: Masafumi
authors.initials: M
authors.lastname: Noda
authors.forename: Masanori
authors.initials: M
authors.lastname: Sugiyama
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D003523:Cycloserine / Q000096:biosynthesis*; D006420:Hemeproteins / Q000235:genetics / Q000378:metabolism*; D006900:Hydroxylation; D019001:Nitric Oxide Synthase / Q000235:genetics / Q000378:metabolism; D013302:Streptomyces / Q000201:enzymology* / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D006420:Hemeproteins; D003523:Cycloserine; D019001:Nitric Oxide Synthase