Biochemical Characterization of Two DNA Ligases from Deinococcus radiodurans

Authors: Le, Donghai; Hua, Xiaoting; Huang, Lifen; Gao, Guanjun; Lu, Huiming; Xu, Zhenjian; Tian, Bing; Hua, Yuejin

Source: Protein and Peptide Letters, Volume 15, Number 6, July 2008 , pp. 600-605(6)

Publisher: Bentham Science Publishers

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Abstract:

Two genes encoding a NAD+-dependent DNA ligase (LigA) and an ATP-dependent DNA ligase (LigB) were identified in the genome of the extremely radioresistant bacterium, Deinococcus radiodurans (DR). The recombinant enzymes expressed in Escherichia coli, were purified to homogeneity and characterized. The optimal temperature and pH value of the two DNA ligases were 60 °C and 7.0, respectively. Their optimal concentration of MgCl2 was 5mM. Their half-lifes of heat inactivation at 100 °C were about 3 min and 5 min, respectively. In addition, the results showed that DRLigB displayed higher activity than DRLigA at stick and blunt ended joining of DNA, indicating that DRLigB is a key DNA ligase of D. radiodurans in DNA recombination and double-strand break repair.

Keywords: DNA ligase; Deinococcus radiodurans; Metal cofactor; Stick and blunt ended DNA ligation; DNA recombination; double-strand break repair

Document Type: Research article

DOI: http://dx.doi.org/10.2174/092986608784967010

Publication date: 2008-07-01

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Protein & Peptide Letters publishes short papers in all important aspects of protein and peptide research, including structural studies, recombinant expression, function, synthesis, enzymology, immunology, molecular modeling, drug design etc. Manuscripts must have a significant element of novelty, timeliness and urgency that merit rapid publication. Reports of crystallisation, and preliminary structure determinations of biologically important proteins are acceptable. Purely theoretical papers are also acceptable provided they provide new insight into the principles of protein/peptide structure and function.