The Caenorhabditis elegans Y87G2A.14 Nudix hydrolase is a peroxisomal coenzyme A diphosphatase.
BACKGROUND
The number of Nudix hydrolase family members varies widely among different organisms. In order to understand the reasons for the particular spectrum possessed by a given organism, the substrate specificity and function of different family members must be established.


RESULTS
The Y87G2A.14 Nudix hydrolase gene product of Caenorhabditis elegans has been expressed as a thioredoxin fusion protein in Escherichia coli and shown to be a CoA diphosphatase with catalytic activity towards CoA and its derivatives. The products of CoA hydrolysis were 3',5'-ADP and 4'-phosphopantetheine with Km and kcat values of 220 microM and 13.8 s(-1) respectively. CoA esters yielded 3',5'-ADP and the corresponding acyl-phosphopantetheine. Activity was optimal at pH 9.5 with 5 mM Mg2+ and fluoride was inhibitory with a Ki of 3 microM. The Y87G2A.14 gene product has a potential C-terminal tripeptide PTS1 peroxisomal targeting signal - SKI. By fusing a Y87G2A.14 cDNA to the C-terminus of yeast-enhanced green fluorescent protein, the enzyme appeared to be targeted to peroxisomes by the SKI signal when transfected into yeast cells. Deletion of SKI abolished specific targeting.


CONCLUSIONS
The presence of related sequences with potential PTS1 or PTS2 peroxisomal targeting signals in other organisms suggests a conserved peroxisomal function for the CoA diphosphatase members of this group of Nudix hydrolases.
AbdelRaheim
Salama R
SR
School of Biological Sciences, Life Sciences Building, University of Liverpool, P,O, Box 147, Liverpool L69 7ZB, UK. salamara@liv.ac.uk
McLennan
Alexander G
AG
D000595:Amino Acid Sequence; D000818:Animals; D017173:Caenorhabditis elegans / Q000201:enzymology*; D003001:Cloning, Molecular; D003065:Coenzyme A / Q000378:metabolism*; D007700:Kinetics; D008969:Molecular Sequence Data; D020675:Peroxisomes / Q000378:metabolism*; D011755:Pyrophosphatases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D016415:Sequence Alignment; D013379:Substrate Specificity; D000096964:Nudix Hydrolases
D003065:Coenzyme A; D011755:Pyrophosphatases; D000096964:Nudix Hydrolases