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STRUCTURE OF A NITRIC OXIDE SYNTHASE HEME PROTEIN FROM BACILLUS SUBTILIS WITH TETRAHYDROFOLATE AND ARGININE BOUNDSTRUCTURE OF A NITRIC OXIDE SYNTHASE HEME PROTEIN FROM BACILLUS SUBTILIS WITH TETRAHYDROFOLATE AND ARGININE BOUND
Structural highlights
FunctionNOSO_BACSU Catalyzes the production of nitric oxide. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedEukaryotic nitric oxide synthases (NOSs) produce nitric oxide to mediate intercellular signaling and protect against pathogens. Recently, proteins homologous to mammalian NOS oxygenase domains have been found in prokaryotes and one from Bacillus subtilis (bsNOS) has been demonstrated to produce nitric oxide [Adak, S., Aulak, K. S., and Stuehr, D. J. (2002) J. Biol. Chem. 277, 16167-16171]. We present structures of bsNOS complexed with the active cofactor tetrahydrofolate and the substrate L-arginine (L-Arg) or the intermediate N(omega)-hydroxy-L-arginine (NHA) to 1.9 or 2.2 A resolution, respectively. The bsNOS structure is similar to those of the mammalian NOS oxygenase domains (mNOS(ox)) except for the absence of an N-terminal beta-hairpin hook and zinc-binding region that interact with pterin and stabilize the mNOS(ox) dimer. Changes in patterns of residue conservation between bacterial and mammalian NOSs correlate to different binding modes for pterin side chains. Residue conservation on a surface patch surrounding an exposed heme edge indicates a likely interaction site for reductase proteins in all NOSs. The heme pockets of bsNOS and mNOS(ox) recognize L-Arg and NHA similarly, although a change from Val to Ile beside the substrate guanidinium may explain the 10-20-fold slower dissociation of product NO from the bacterial enzyme. Overall, these structures suggest that bsNOS functions naturally to produce nitrogen oxides from L-Arg and NHA in a pterin-dependent manner, but that the regulation and purpose of NO production by NOS may be quite different in B. subtilis than in mammals. Structure of a nitric oxide synthase heme protein from Bacillus subtilis.,Pant K, Bilwes AM, Adak S, Stuehr DJ, Crane BR Biochemistry. 2002 Sep 17;41(37):11071-9. PMID:12220171[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences |
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