Nucleic Acids Research, 2001, Vol. 29, No. 14 3099-3107
© 2001 Oxford University Press
Biochemical characterization of a novel hypoxanthine/xanthine dNTP pyrophosphatase from Methanococcus jannaschii
1Structural Biology Research Center, Korea Institute of Science and Technology, PO Box 131, Cheongryang, Seoul, Korea and 2The Graduate School of Biotechnology, Korea University, Seoul 136-701, Korea
A novel dNTP pyrophosphatase, Mj0226 from Methanococcus jannaschii, which catalyzes the hydrolysis of nucleoside triphosphates to the monophosphate and PPi, has been characterized. Mj0226 protein catalyzes hydrolysis of two major substrates, dITP and XTP, suggesting that the 6-keto group of hypoxanthine and xanthine is critical for interaction with the protein. Under optimal reaction conditions the kcat /Km value for these substrates was 
10 000 times that with dATP. Neither endonuclease nor 3'-exonuclease activities were detected in this protein. Interestingly, dITP was efficiently inserted opposite a dC residue in a DNA template and four dNTPs were also incorporated opposite a hypoxanthine residue in template DNA by DNA polymerase I. Two protein homologs of Mj0226 from Escherichia coli and Archaeoglobus fulgidus were also cloned and purified. These have catalytic activities similar to Mj0226 protein under optimal conditions. The implications of these results have significance in understanding how homologous proteins, including Mj0226, act biologically in many organisms. It seems likely that Mj0226 and its homologs have a major role in preventing mutations caused by incorporation of dITP and XTP formed spontaneously in the nucleotide pool into DNA. This report is the first identification and functional characterization of an enzyme hydrolyzing non-canonical nucleotides, dITP and XTP.
* To whom correspondence should be addressed. Tel: +82 2 958 5933; Fax: +82 2 958 5939; Email: yshan2{at}kist.re.kr
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  E. Rotman and A. Kuzminov The mutT Defect Does Not Elevate Chromosomal Fragmentation in Escherichia coli Because of the Surprisingly Low Levels of MutM/MutY-Recognized DNA Modifications J. Bacteriol., October 1, 2007; 189(19): 6976 - 6988. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N. E. Burgis and R. P. Cunningham Substrate Specificity of RdgB Protein, a Deoxyribonucleoside Triphosphate Pyrophosphohydrolase J. Biol. Chem., February 9, 2007; 282(6): 3531 - 3538. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. Budke and A. Kuzminov Hypoxanthine Incorporation Is Nonmutagenic in Escherichia coli. J. Bacteriol., September 1, 2006; 188(18): 6553 - 6560. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. Lukas and A. Kuzminov Chromosomal Fragmentation Is the Major Consequence of the rdgB Defect in Escherichia coli Genetics, February 1, 2006; 172(2): 1359 - 1362. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. Gruz, M. Shimizu, F. M. Pisani, M. D. Felice, Y. Kanke, and T. Nohmi Processing of DNA lesions by archaeal DNA polymerases from Sulfolobus solfataricus Nucleic Acids Res., July 15, 2003; 31(14): 4024 - 4030. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Zhang, Y. Zhang, and M. Inouye Thermotoga maritima MazG Protein Has Both Nucleoside Triphosphate Pyrophosphohydrolase and Pyrophosphatase Activities J. Biol. Chem., June 6, 2003; 278(24): 21408 - 21414. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. E. Burgis, J. J. Brucker, and R. P. Cunningham Repair System for Noncanonical Purines in Escherichia coli J. Bacteriol., May 15, 2003; 185(10): 3101 - 3110. [Abstract] [Full Text] [PDF]
|
|