title: Structure of a Nudix protein from Pyrobaculum aerophilum reveals a dimer with two intersubunit beta-sheets.
abstract: Nudix proteins, formerly called MutT homolog proteins, are a large family of proteins that play an important role in reducing the accumulation of potentially toxic compounds inside the cell. They hydrolyze a wide variety of substrates that are mainly composed of a nucleoside diphosphate linked to some other moiety X and thus are called Nudix hydrolases. Here, the crystal structure of a Nudix hydrolase from the hyperthermophilic archaeon Pyrobaculum aerophilum is reported. The structure was determined by the single-wavelength anomalous scattering method with data collected at the peak anomalous wavelength of an iridium-derivatized crystal. It reveals an extensive dimer interface, with each subunit contributing two strands to the beta-sheet of the other subunit. Individual subunits consist of a mixed highly twisted and curved beta-sheet of 11 beta-strands and two alpha-helices, forming an alpha-beta-alpha sandwich. The conserved Nudix box signature motif, which contains the essential catalytic residues, is located at the first alpha-helix and the beta-strand and loop preceding it. The unusually short connections between secondary-structural elements, together with the dimer form of the structure, are likely to contribute to the thermostability of the P. aerophilum Nudix protein.
authors.affiliation: UCLA-DOE Laboratory of Structure Biology, 611 Charles E. Young Drive East, 201 Boyer Hall, Los Angeles, CA 90095-1570, USA.
authors.forename: Shuishu
authors.initials: S
authors.lastname: Wang
authors.forename: Cameron
authors.initials: C
authors.lastname: Mura
authors.forename: Michael R
authors.initials: MR
authors.lastname: Sawaya
authors.forename: Duilio
authors.initials: D
authors.lastname: Cascio
authors.forename: David
authors.initials: D
authors.lastname: Eisenberg
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D017124:Conserved Sequence; D003460:Crystallization; D019281:Dimerization; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D011755:Pyrophosphatases / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D013463:Sulfuric Acid Esters / Q000737:chemistry; D019624:Thermoproteaceae / Q000737:chemistry*; D000096964:Nudix Hydrolases
chemical_list: D011755:Pyrophosphatases; D013463:Sulfuric Acid Esters; D000096964:Nudix Hydrolases