title: Solution structure of hypothetical Nudix hydrolase DR0079 from extremely radiation-resistant Deinococcus radiodurans bacterium.
abstract: Using nuclear magnetic resonance (NMR) based methods, including residual dipolar coupling restraints, we have determined the solution structure of the hypothetical Deinococcus radiodurans Nudix protein DR0079 (171 residues, MW = 19.3 kDa). The protein contains eight beta-strands and three alpha-helices organized into three subdomains: an N-terminal beta-sheet (1-34), a central Nudix core (35-140), and a C-terminal helix-turn-helix (141-171). The Nudix core and the C-terminal helix-turn-helix form the fundamental fold common to the Nudix family, a large mixed beta-sheet sandwiched between alpha-helices. The residues that compose the signature Nudix sequence, GX5EX7REUXEEXGU (where U = I, L, or V and X = any amino acid), are contained in a turn-helix-turn motif on the face of the mixed beta-sheet. Chemical shift mapping experiments suggest that DR0079 binds Mg2+. Experiments designed to determine the biological function of the protein indicate that it is not a type I isopentenyl-diphosphate delta-isomerase and that it does not bind alpha,beta-methyleneadenosine 5'-triphosphate (AMPCPP) or guanosine 5'-[beta,gamma-imido]triphosphate (GMPPNP). In this article, the structure of DR0079 is compared to other known Nudix protein structures, a potential substrate-binding surface is proposed, and its possible biological function is discussed.
authors.affiliation: Fundamental Sciences, Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
authors.forename: Garry W
authors.initials: GW
authors.lastname: Buchko
authors.forename: Shuisong
authors.initials: S
authors.lastname: Ni
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Holbrook
authors.forename: Michael A
authors.initials: MA
authors.lastname: Kennedy
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001665:Binding Sites; D034301:Deinococcus / Q000201:enzymology* / Q000502:physiology; D008274:Magnesium / Q000378:metabolism / Q000494:pharmacology; D008345:Manganese / Q000378:metabolism / Q000494:pharmacology; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D017433:Protein Structure, Secondary / Q000187:drug effects; D011755:Pyrophosphatases / Q000737:chemistry* / Q000378:metabolism; D011836:Radiation Tolerance; D016415:Sequence Alignment; D012996:Solutions; D013329:Structure-Activity Relationship; D000096964:Nudix Hydrolases
chemical_list: D008274:Magnesium; D008345:Manganese; D011755:Pyrophosphatases; D012996:Solutions; D000096964:Nudix Hydrolases