title: Comprehensive analysis of cytosolic Nudix hydrolases in Arabidopsis thaliana.
abstract: Nudix hydrolases are a family of proteins that catalyze the hydrolysis of a variety of nucleoside diphosphate derivatives. Twenty-four genes of the Nudix hydrolase homologues (AtNUDTs) with predicted localizations in the cytosol, chloroplasts, and mitochondria exist in Arabidopsis thaliana. Here, we demonstrated the comprehensive analysis of nine types of cytosolic AtNUDT proteins (AtNUDT1, -2, -4, -5, -6, -7, -9, -10, and -11). The recombinant proteins of AtNUDT2, -6, -7, and -10 showed both ADP-ribose and NADH pyrophosphatase activities with significantly high affinities compared with those of animal and yeast enzymes. The expression of each AtNUDT is individually regulated in different tissues. These findings suggest that most cytosolic AtNUDTs may substantially function in the sanitization of potentially hazardous ADP-ribose and the regulation of the cellular NADH/NAD(+) ratio in plant cells. On the other hand, the AtNUDT1 protein had the ability to hydrolyze 8-oxo-dGTP with a K(m) value of 6.8 mum and completely suppress the increased frequency of spontaneous mutations in the Escherichia coli mutT(-) strain, indicating that AtNUDT1 is a functional homologue of E. coli MutT in A. thaliana and is involved in the prevention of spontaneous mutation. The results obtained here suggest that the plant Nudix family has evolved in a specific manner that differs from that of yeast and humans.
authors.affiliation: Department of Advanced Bioscience, Faculty of Agriculture, Kinki University, 3327-204 Nakamachi, Nara 631-8505, Japan.
authors.forename: Takahisa
authors.initials: T
authors.lastname: Ogawa
authors.forename: Yayoi
authors.initials: Y
authors.lastname: Ueda
authors.forename: Kazuya
authors.initials: K
authors.lastname: Yoshimura
authors.forename: Shigeru
authors.initials: S
authors.lastname: Shigeoka
mesh_terms: D000246:Adenosine Diphosphate Ribose / Q000737:chemistry; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology*; D029681:Arabidopsis Proteins / Q000096:biosynthesis / Q000737:chemistry*; D002384:Catalysis; D002736:Chloroplasts / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D003600:Cytosol / Q000201:enzymology* / Q000378:metabolism; D003848:Deoxyguanine Nucleotides / Q000737:chemistry; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry; D005816:Genetic Complementation Test; D006801:Humans; D006868:Hydrolysis; D007700:Kinetics; D008969:Molecular Sequence Data; D005810:Multigene Family; D009154:Mutation; D010744:Phosphoric Monoester Hydrolases / Q000737:chemistry; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D011755:Pyrophosphatases / Q000096:biosynthesis / Q000737:chemistry* / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
chemical_list: D029681:Arabidopsis Proteins; D003848:Deoxyguanine Nucleotides; D029968:Escherichia coli Proteins; D011994:Recombinant Proteins; C078206:8-oxodeoxyguanosine triphosphate; D000246:Adenosine Diphosphate Ribose; D010744:Phosphoric Monoester Hydrolases; C471296:NUDT1 protein, Arabidopsis; D011755:Pyrophosphatases; C052211:mutT protein, E coli; C021899:nucleotide pyrophosphatase