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41.
Methyl-directed site-specific DNA endonucleases (MD endonucleases) are a small group of enzymes that specifically cleave only methylated DNA. The group includes N6-methyladenine- and 5-methylcytosine-directed enzymes. Although poorly understood, MD endonucleases are of interest for both basic research and application in biotechnology and epigenomics. The review for the first time summarizes the properties of MD endonucleases and considers their role in the bacterial cell and their possible uses in biotechnology and epigenomics. 相似文献
42.
Tarasova MV Kuznetsov VV Netesova NA Gonchar DA Degtyarev SKh 《Biochemistry. Biokhimii?a》2010,75(12):1484-1490
A restriction-modification system from Bacillus psychrodurans AC (recognition sequence 5′-CCGC-3′) comprises two DNA methyltransferases: M1.BspACI and M2.BspACI. The bspACIM1 gene was cloned in the pJW2 vector and expressed in Escherichia coli cells. High-purity M1.BspACI preparation has been obtained by chromatography on different carriers. M1.BspACI has a temperature
optimum of 30°C and demonstrates maximum activity at pH 8.0. M1.BspACI modifies the first cytosine in the recognition sequence
5′-CCGC-3′. The kinetic parameters of M1.BspACI DNA methylation are as follows: K
m for phage λ DNA is 0.053 μM and K
m for S-adenosyl-L-methionine is 5.1 μM. The catalytic constant (k
cat) is 0.095 min−1. 相似文献
43.
Structural relationship within the family of the thiamine diphosphate-dependent 2-oxo acid dehydrogenases was analyzed by combining different methods of sequence alignment with crystallographic and enzymological studies of the family members. For the first time, the sequence similarity of the homodimeric 2-oxoglutarate dehydrogenase to heterotetrameric 2-oxo acid dehydrogenases is established. The presented alignment of the catalytic domains of the dehydrogenases of pyruvate, branched-chain 2-oxo acids and 2-oxoglutarate unravels the sequence markers of the substrate specificity and the essential residues of the family members without the 3D structures resolved. Predicted dual substrate specificity of some of the 2-oxo acid dehydrogenases was confirmed experimentally. The results were used to decipher functions of the two hypothetical proteins of animal genomes, OGDHL and DHTKD1, similar to the 2-oxoglutarate dehydrogenase. Conservation of all the essential residues confirmed their catalytic competence. Sequence analysis indicated that OGDHL represents a previously unknown isoform of the 2-oxoglutarate dehydrogenase, whereas DHTKD1 differs from the homologs at the N-terminus and substrate binding pocket. The differences suggest changes in heterologous protein interactions and accommodation of more polar and/or bulkier structural analogs of 2-oxoglutarate, such as 2-oxoadipate, 2-oxo-4-hydroxyglutarate, or products of the carboligase reaction between a 2-oxodicarboxylate and glyoxylate or acetaldehyde. The signatures of the Ca2+-binding sites were found in the Ca2+-activated 2-oxoglutarate dehydrogenase and OGDHL, but not in DHTKD1. Mitochondrial localization was predicted for OGDHL and DHTKD1, with DHTKD1 probably localized also to nuclei. Medical implications of the obtained results are discussed in view of the possible associations of the 2-oxo acid dehydrogenases and DHTKD1 with neurodegeneration and cancer. 相似文献
44.
S. V. Antoshina A. A. Selishcheva G. M. Sorokoumova E. A. Utkina N. S. Degtyarev V. I. Shvets 《Applied Biochemistry and Microbiology》2005,41(1):18-23
The effect of flavonoids of various structures (baikalein, baikalin, quercetin, dihydroquercetin, genistein, and daidzein) on the process of formation of lipid hydroperoxides during thermoinduced autooxidation of neutral lipids of animal origin is studied. The minimum inhibitory concentration of isoflavones was found to be equal to 10-3 M. The effective inhibitory concentration of other flavonoids (except baikalin) was equal to 10-4 M. Baikalin was an effective promoter of lipid peroxidation. The antioxidant activity of the flavonoids tested was calculated, taking ionol as a reference.Translated from Prikladnaya Biokhimiya i Mikrobiologiya, Vol. 41, No. 1, 2005, pp. 23–28.Original Russian Text Copyright © 2005 by Antoshina, Selishcheva, Sorokoumova, Utkina, Degtyarev, Shvets. 相似文献
45.
Chernukhin VA Kashirina YG Sukhanova KS Abdurashitov MA Gonchar DA Degtyarev SKh 《Biochemistry. Biokhimii?a》2005,70(6):685-691
A gene encoding DNA methyltransferase (methylase) FauIA of the restriction-modification system FauI from Flavobacterium aquatile (recognizing sequence 5'-CCCGC-3') was cloned in pJW vector. The latter was used for transformation of E. coli RRI cells followed by subsequent thermoinduction and biomass elaboration. Highly purified DNA methyltransferase FauIA preparation was obtained using chromatography on different sorbents. The molecular mass of the isolated enzyme of about 39 kD corresponds to its theoretical value. The enzyme was characterized by temperature and pH optima of 33 degrees C and pH 7.5, respectively. Methylation of a synthetic oligonucleotide by FauIA methylase followed by its cleavage with various restrictases and analysis of the resultant restriction fragments revealed that FauIA methylase modified the second cytosine residue in the sequence 5'-CCCGC-3'. Kinetic analysis revealed Km and catalytic constant values of 0.16 microM and 0.05 min(-1), respectively. 相似文献
46.
47.
Ilinsky V. V. Kozlova E. M. Degtyarev S. Kh. Yankovsky N. K. Makeev V. J. 《Biophysics》2020,65(6):889-893
Biophysics - The MinION system (Oxford Nanopore Technologies, United Kingdom) was used to directly sequence genomic DNAs of two recombinant Escherichia coli strains. One strain carried a plasmid... 相似文献
48.
Nikishina M. V. Makarova S. I. Akishev A. G. Vavilin V. A. Degtyarev S. Kh. Lyakhovich V. V. 《Russian Journal of Genetics》2004,40(11):1288-1291
Restriction analysis of the NAT2 gene was carried out in inhabitants of Novosibirsk. Polymorphism of this gene for nine known point mutations was studied in a sample of Novosibirsk residents consisting of 109 healthy Caucasians. The frequencies of these mutations did not significantly differ from the frequencies reported for Caucasian populations of other countries. In 79 patients with lung cancer, a region of the NAT2 gene that includes 29.7% of the coding sequence was analyzed for the new mutations by the RFLP analysis. No new mutations were found in this group. 相似文献
49.
V. G. Degtyarev 《Contemporary Problems of Ecology》2008,1(5):564-567
The probability of contacts of the populations of waterbirds of Northeastern Asia with chemical pollutants is considered on the basis of analysis of the literature and archive data on production and application of pesticides and levels of industrial chemical pollution. 相似文献
50.
Russian Journal of Genetics - 相似文献