An intrinsic 5′-deoxyribose-5-phosphate lyase activity in DNA polymerase beta from Leishmania infantum supports a role in DNA repair

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• 作者：Ana Alonso ; Gloria Terrados ; Angel J. Picher ; Rafael Giraldo ; Luis Blanco and Vicente Larraga
• 关键词：Leishmania ; DNA polymerase beta ; BER ; dRP lyase activity
• 刊名：DNA Repair
• 出版年：2006
• 出版时间：5 January 2006
• 年：2006
• 卷：5
• 期：1
• 页码：89-101
• 全文大小：520 K

文摘

Leishmania infantum is a parasitic protozoan which infects humans. This paper reports the expression in Escherichia coli and purification of the L. infantum gene product (AF182167), as well as its characterization as a DNA polymerase beta (Polβ)-like, template-dependent DNA repair enzyme, with a metal preference for Mn²⁺ over Mg²⁺. As is the case with mammalian Polβ and DNA polymerase lambda (Polλ), L. infantum DNA polymerase beta (Li Polβ) prefers gapped-DNA substrates having a 5′-phosphate end, in agreement with its role in DNA repair reactions. Purified Li Polβ also displayed a 5′-deoxyribose-5-phosphate (dRP) lyase activity, consistent with a β-elimination mechanism. The concerted action of dRP lyase and DNA polymerization activities of Li Polβ on a uracil-containing DNA suggests its participation in “single-nucleotide” base excision repair (BER). Analysis of Li Polβ DNA polymerization activity at different stages of the L. infantum infective cycle supports a role for Li Polβ in nuclear DNA repair after the oxidative damage occurring inside the macrophage.