Abstract
We cloned, expressed, and characterized a hemeprotein from Deinococcus radiodurans (D. radiodurans NO synthase, deiNOS) whose sequence is 34% identical to the oxygenase domain of mammalian NO synthases (NOSoxys). deiNOS was dimeric, bound substrate Arg and cofactor tetrahydrobiopterin, and had a normal heme environment, despite its missing N-terminal structures that in NOSoxy bind Zn(2+) and tetrahydrobiopterin and help form an active dimer. The deiNOS heme accepted electrons from a mammalian NOS reductase and generated NO at rates that met or exceeded NOSoxy. Activity required bound tetrahydrobiopterin or tetrahydrofolate and was linked to formation and disappearance of a typical heme-dioxy catalytic intermediate. Thus, bacterial NOS-like proteins are surprisingly similar to mammalian NOSs and broaden our perspective of NO biochemistry and function.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Amino Acid Sequence
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Animals
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Arginine / chemistry
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Arginine / metabolism
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Biopterins / analogs & derivatives*
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Biopterins / chemistry
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Catalysis
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Citrulline / chemistry
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Cloning, Molecular
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Dimerization
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Dithiothreitol / pharmacology
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Dose-Response Relationship, Drug
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Electrons
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Heme / chemistry
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Hydrogen Peroxide / chemistry
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Kinetics
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Ligands
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Models, Chemical
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Models, Molecular
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Molecular Sequence Data
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NADP / metabolism
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Nitric Oxide / chemistry
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Nitric Oxide Synthase / biosynthesis
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Nitric Oxide Synthase / chemistry*
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Nitric Oxide Synthase / genetics*
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Nitric Oxide Synthase / metabolism
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Oxidation-Reduction
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Protein Binding
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Protein Conformation
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Protein Structure, Tertiary
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Sequence Homology, Amino Acid
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Thermus / enzymology*
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Time Factors
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Zinc / metabolism
Substances
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Ligands
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Biopterins
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Citrulline
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Nitric Oxide
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Heme
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NADP
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Arginine
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Hydrogen Peroxide
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Nitric Oxide Synthase
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sapropterin
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Zinc
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Dithiothreitol