Characterization of the Mn super(2+)-stimulated (di)adenosine polyphosphate hydrolase encoded by the Deinococcus radiodurans DR2356 nudix gene

The DR2356 nudix hydrolase gene from Deinococcus radiodurans has been cloned and the product expressed as an 18 kDa histidine-tagged protein. The enzyme hydrolysed adenosine and diadenosine polyphosphates, always generating ATP as one of the initial products. ATP and other (deoxy)nucleoside triphosp...

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Bibliographic Details
Published in:Archives of microbiology 2006-11, Vol.186 (5), p.415-424
Main Authors: Fisher, David I, Cartwright, Jared L, McLennan, Alexander G
Format: Article
Language:English
Subjects:
Deinococcus radiodurans
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Summary:The DR2356 nudix hydrolase gene from Deinococcus radiodurans has been cloned and the product expressed as an 18 kDa histidine-tagged protein. The enzyme hydrolysed adenosine and diadenosine polyphosphates, always generating ATP as one of the initial products. ATP and other (deoxy)nucleoside triphosphates were also substrates, yielding (d)NDP and Pi as products. The DR2356 protein was most active at pH 8.6-9.0 and showed a strong preference for Mn super(2+) as activating cation. Mg super(2+) ions at 15 mM supported only 5% of the activity achieved with 2 mM Mn super(2+). K sub(m) and k sub(cat) values for diadenosine tetra-, penta- and hexaphosphates were 2.0, 2.4 and 1.1 mu M and 11.4, 28.6 and 12.0 s super(-1), respectively, while for GTP they were 20.3 mu M and 1.8 s super(-1), respectively. The K sub(m )for adenosine 5'-pentaphosphate was
ISSN:0302-8933
DOI:10.1007/s00203-006-0155-z