Abstract
Nudix hydrolases act to hydrolyze various nucleoside diphosphate derivatives. A. thaliana contains 27 genes encoding Nudix hydrolase homologues (AtNUDXs) with a predicted distribution in the cytosol (AtNUDX1~11, 25), mitochondria (AtNUDX12~18), and chloroplasts (AtNUDX19~24, 26, 27). Previously, we have reported that AtNUDX11 specifically hydrolyzes CoA (J. Biol. Chem. 2005 280: 25277-83). The UPF0035 motif for CoA pyrophosphohydrolases was conserved in not only AtNUDX11 but also AtNUDX15 and AtNUDX22. Here we analyzed the molecular characterization of these CoA pyrophosphohydrolases. Recombinant AtNUDX15 hydrolyzed CoA. Furthermore, AtNUDX11 and 15 also showed activities toward CoA derivatives, such as malonyl-CoA and lauroyl-CoA. No activity toward any nucleoside diphosphate derivatives was observed in AtNUDX22. Interestingly, predicted mitochondrial (AtNUDX15) and peroxisomal (AtNUDX15a) isoforms were produced from AtNUDX15 by an alternative splicing event. These results suggest that AtNUDX11 and 15 may directly or indirectly influenced to CoA-relating metabolisms such as TCA cycle and β-oxidation in mitochondria and peroxisome.
