Uracil-DNA glycosylase-DNA substrate and product structures: Conformational strain promotes catalytic efficiency by coupled stereoelectronic effects
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چکیده
منابع مشابه
Uracil-DNA glycosylase. Purification and properties of uracil-DNA glycosylase from Micrococcus luteus.
A uracil-DNA-glycosylase from Micrococcus luteus has been purified more than 3,000-fold. The enzyme preparation appears homogeneous, according to the results of sodium dodecyl sulfate-polyacrylamide gel electrophoresis. It is devoid of nonspecific endonucleases, specific endonucleases for apurinic and apyrimidinic sites, 3-methyladenine or 7-methylguanine-DNA-glycosylases. It behaves as a monom...
متن کاملUracil DNa-glycosylase from HeLa cells: general properties, substrate specificity and effect of uracil analogs.
Uracil-DNA glycosylase was partially purified from HeLa cells. Various substrates containing [3H]dUMP residues were prepared by nick-translation of calf thymus DNA. The standard substrate was double-stranded DNA with [3H]dUMP located internally in the chain. Compared to the release of uracil from this substrate, a 3-fold increase in the rate was seen with single-stranded DNA, and a 20-fold redu...
متن کاملInefficient excision of uracil from loop regions of DNA oligomers by E. coli uracil DNA glycosylase.
Kinetic parameters for uracil DNA glycosylase (E. coli)-catalysed excision of uracil from DNA oligomers containing dUMP in different structural contexts were determined. Our results show that single-stranded oligonucleotides (unstructured) are used as somewhat better substrates than the double-stranded oligonucleotides. This is mainly because of the favourable Vmax value of the enzyme for singl...
متن کاملMutations at Arginine 276 transform human uracil-DNA glycosylase into a single-stranded DNA-specific uracil-DNA glycosylase.
To investigate the role of Arginine 276 in the conserved leucine-loop of human uracil-DNA glycosylase (UNG), the effects of six R276 amino acid substitutions (C, E, H, L, W, and Y) on nucleotide flipping and enzyme conformational change were determined using transient and steady state, fluorescence-based, kinetic analysis. Relative to UNG, the mutant proteins exhibited a 2.6- to 7.7-fold reduct...
متن کاملCrystal structure of mimivirus uracil-DNA glycosylase
Cytosine deamination induced by stresses or enzymatic catalysis converts deoxycytidine into deoxyuridine, thereby introducing a G to A mutation after DNA replication. Base-excision repair to correct uracil to cytosine is initiated by uracil-DNA glycosylase (UDG), which recognizes and eliminates uracil from DNA. Mimivirus, one of the largest known viruses, also encodes a distinctive UDG gene con...
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ژورنال
عنوان ژورنال: Proceedings of the National Academy of Sciences
سال: 2000
ISSN: 0027-8424,1091-6490
DOI: 10.1073/pnas.97.10.5083