Structural highlights
Function
[YJJX_ECOLI] Phosphatase that hydrolyzes non-canonical purine nucleotides such as XTP and ITP to their respective diphosphate derivatives. Probably excludes non-canonical purines from DNA precursor pool, thus preventing their incorporation into DNA and avoiding chromosomal lesions. ITP is the best substrate, followed by XTP, GDP or dITP. Also implicated in the resistance against the thiamine metabolism inhibitors bacimethrin and CF3-HMP.[1]
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
Inosine triphosphate (ITP) and xanthosine triphosphate (XTP) are formed upon deamination of ATP and GTP as a result of exposure to chemical mutagens and oxidative damage. Nucleic acid synthesis requires safeguard mechanisms to minimize undesired lethal incorporation of ITP and XTP. Here, we present the crystal structure of YjjX, a protein of hitherto unknown function. The three-dimensional fold of YjjX is similar to those of Mj0226 from Methanococcus janschii, which possesses nucleotidase activity, and of Maf from Bacillus subtilis, which can bind nucleotides. Biochemical analyses of YjjX revealed it to exhibit specific phosphatase activity for inosine and xanthosine triphosphates and have a possible interaction with elongation factor Tu. The enzymatic activity of YjjX as an inosine/xanthosine triphosphatase provides evidence for a plausible protection mechanism by clearing the noncanonical nucleotides from the cell during oxidative stress in E. coli.
Identification of an ITPase/XTPase in Escherichia coli by structural and biochemical analysis.,Zheng J, Singh VK, Jia Z Structure. 2005 Oct;13(10):1511-20. PMID:16216582[2]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Zheng J, Singh VK, Jia Z. Identification of an ITPase/XTPase in Escherichia coli by structural and biochemical analysis. Structure. 2005 Oct;13(10):1511-20. PMID:16216582 doi:10.1016/j.str.2005.07.007
- ↑ Zheng J, Singh VK, Jia Z. Identification of an ITPase/XTPase in Escherichia coli by structural and biochemical analysis. Structure. 2005 Oct;13(10):1511-20. PMID:16216582 doi:10.1016/j.str.2005.07.007
