کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1980189 1061828 2013 13 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
The excision of 3′ penultimate errors by DNA polymerase I and its role in endonuclease V-mediated DNA repair
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی زیست شیمی
پیش نمایش صفحه اول مقاله
The excision of 3′ penultimate errors by DNA polymerase I and its role in endonuclease V-mediated DNA repair
چکیده انگلیسی


• Endonuclease V, which does not independently turn over in vitro, does do so in a multi-enzyme system using T-I substrate.
• The 3′-5′ exonuclease activity of DNA polymerase I play a major role for deoxyinosine removal in endo V pathway.
• The proofreading activity of pol I can actively correct penultimate errors including mismatches and damaged bases.

Deamination of adenine can occur spontaneously under physiological conditions, and is enhanced by exposure of DNA to ionizing radiation, UV light, nitrous acid, or heat, generating the highly mutagenic lesion of deoxyinosine in DNA. Such DNA lesions tends to generate A:T to G:C transition mutations if unrepaired. In Escherichia coli, deoxyinosine is primarily removed through a repair pathway initiated by endonuclease V (endo V). In this study, we compared the repair of three mutagenic deoxyinosine lesions of A-I, G-I, and T-I using E. coli cell-free extracts as well as reconstituted protein system. We found that 3′-5′ exonuclease activity of DNA polymerase I (pol I) was very important for processing all deoxyinosine lesions. To understand the nature of pol I in removing damaged nucleotides, we systemically analyzed its proofreading to 12 possible mismatches 3′-penultimate of a nick, a configuration that represents a repair intermediate generated by endo V. The results showed all mismatches as well as deoxyinosine at the 3′ penultimate site were corrected with similar efficiency. This study strongly supports for the idea that the 3′-5′ exonuclease activity of E. coli pol I is the primary exonuclease activity for removing 3′-penultimate deoxyinosines derived from endo V nicking reaction.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: DNA Repair - Volume 12, Issue 11, November 2013, Pages 899–911
نویسندگان
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