کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1981277 1061915 2009 11 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Plant and fungal Fpg homologs are formamidopyrimidine DNA glycosylases but not 8-oxoguanine DNA glycosylases
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی زیست شیمی
پیش نمایش صفحه اول مقاله
Plant and fungal Fpg homologs are formamidopyrimidine DNA glycosylases but not 8-oxoguanine DNA glycosylases
چکیده انگلیسی

Formamidopyrimidine DNA glycosylase (Fpg) and endonuclease VIII (Nei) share an overall common three-dimensional structure and primary amino acid sequence in conserved structural motifs but have different substrate specificities, with bacterial Fpg proteins recognizing formamidopyrimidines, 8-oxoguanine (8-oxoG) and its oxidation products guanidinohydantoin (Gh), and spiroiminodihydantoin (Sp) and bacterial Nei proteins recognizing primarily damaged pyrimidines. In addition to bacteria, Fpg has also been found in plants, while Nei is sparsely distributed among the prokaryotes and eukaryotes. Phylogenetic analysis of Fpg and Nei DNA glycosylases demonstrated, with 95% bootstrap support, a clade containing exclusively sequences from plants and fungi. Members of this clade exhibit sequence features closer to bacterial Fpg proteins than to any protein designated as Nei based on biochemical studies. The Candida albicans (Cal) Fpg DNA glycosylase and a previously studied Arabidopsis thaliana (Ath) Fpg DNA glycosylase were expressed, purified and characterized. In oligodeoxynucleotides, the preferred glycosylase substrates for both enzymes were Gh and Sp, the oxidation products of 8-oxoG, with the best substrate being a site of base loss. GC/MS analysis of bases released from γ-irradiated DNA show FapyAde and FapyGua to be excellent substrates as well. Studies carried out with oligodeoxynucleotide substrates demonstrate that both enzymes discriminated against A opposite the base lesion, characteristic of Fpg glycosylases. Single turnover kinetics with oligodeoxynucleotides showed that the plant and fungal glycosylases were most active on Gh and Sp, less active on oxidized pyrimidines and exhibited very little or no activity on 8-oxoG. Surprisingly, the activity of AthFpg1 on an AP site opposite a G was extremely robust with a kobs of over 2500 min−1.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: DNA Repair - Volume 8, Issue 5, 1 May 2009, Pages 643–653
نویسندگان
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