Srinath, Thiruneelakantan ; Bharti, Sanjay Kumar ; Varshney, Umesh (2007) Substrate specificities and functional characterization of a thermo-tolerant uracil DNA glycosylase (UdgB) from Mycobacterium tuberculosis DNA Repair, 6 (10). pp. 1517-1528. ISSN 1568-7864
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Official URL: http://www.sciencedirect.com/science/article/pii/S...
Related URL: http://dx.doi.org/10.1016/j.dnarep.2007.05.001
Abstract
Uracil DNA glycosylases (UDGs) excise uracil from DNA and initiate the base (uracil) excision repair pathway. Ung, a highly conserved protein, is the only UDG characterized so far in mycobacteria. Here, we show that Rv1259 from Mycobacterium tuberculosis codes for a double-stranded DNA (dsDNA) specific UDG (MtuUdgB). MtuUdgB is thermo-tolerant, contains Fe-S cluster and, in addition to uracil, it excises ethenocytosine and hypoxanthine from dsDNA. MtuUdgB is product inhibited by AP-site containing dsDNA but not by uracil. While MtuUdgB excises uracil present as a single-nucleotide bulge in dsDNA, it is insensitive to inhibition by dsDNA containing AP-site in the bulge. Interestingly, in the presence of cellular factors, the uracil excision activity of MtuUdgB is enhanced, and when introduced into E. coli (ung−), it rescues its mutator phenotype and prevents C to T mutations in DNA. Novel features of the mechanism of action of MtuUdgB and the physiological significance of the family 5 UDG in mycobacteria have been discussed.
Item Type: | Article |
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Source: | Copyright of this article belongs to Elsevier Science. |
Keywords: | Family 5 UDG; Fe-S Cluster; Ethenocytosine; Hypoxanthine |
ID Code: | 56224 |
Deposited On: | 23 Aug 2011 11:57 |
Last Modified: | 23 Aug 2011 11:57 |
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