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1.
K.?V.?SereginEmail author M.?V.?Chudinov A.?M.?Yurkevich V.?I.?Shvets 《Russian Journal of Bioorganic Chemistry》2005,31(2):135-138
An efficient method of reduction of 3-azido-3-deoxythymidine and its 5-protected derivatives to 3-aminothymidine derivatives on a palladium catalyst using ammonium formate as a source of hydrogen was suggested.__________Translated from Bioorganicheskaya Khimiya, Vol. 31, No. 2, 2005, pp. 147–150.Original Russian Text Copyright © 2005 by Seregin, Chudinov, Yurkevich, Shvets. 相似文献
2.
Huidong Zhang 《Journal of molecular biology》2010,395(5):1007-1018
Translesion DNA polymerases are more efficient at bypass of many DNA adducts than replicative polymerases. Previous work with the translesion polymerase Sulfolobus solfataricus Dpo4 showed a decrease in catalytic efficiency during bypass of bulky N2-alkyl guanine (G) adducts with N2-isobutylG showing the largest effect, decreasing ∼ 120-fold relative to unmodified deoxyguanosine (Zhang, H., Eoff, R. L., Egli, M., Guengerich, F. P. Versatility of Y-family Sulfolobus solfataricus DNA polymerase Dpo4 in translation synthesis past bulky N2-alkylguanine adducts. J. Biol. Chem. 2009; 284: 3563-3576). The effect of adduct size on individual catalytic steps has not been easy to decipher because of the difficulty of distinguishing early noncovalent steps from phosphodiester bond formation. We developed a mutant with a single Trp (T239W) to monitor fluorescence changes associated with a conformational change that occurs after binding a correct 2′-deoxyribonucleoside triphosphate (Beckman, J. W., Wang, Q., Guengerich, F. P. Kinetic analysis of nucleotide insertion by a Y-family DNA polymerase reveals conformational change both prior to and following phosphodiester bond formation as detected by tryptophan fluorescence. J. Biol. Chem. 2008; 283: 36711-36723) and, in the present work, utilized this approach to monitor insertion opposite N2-alkylG-modified oligonucleotides. We estimated maximal rates for the forward conformational step, which coupled with measured rates of product formation yielded rate constants for the conformational step (both directions) during insertion opposite several N2-alkylG adducts. With the smaller N2-alkylG adducts, the conformational rate constants were not changed dramatically (< 3-fold), indicating that the more sensitive steps are phosphodiester bond formation and partitioning into inactive complexes. With the larger adducts (≥ (2-naphthyl)methyl), the absence of fluorescence changes suggests impaired ability to undergo an appropriate conformational change, consistent with previous structural work. 相似文献
3.
M. V. Jasko A. V. Shipitsyn A. L. Khandazhinskaya E. A. Shirokova P. N. Sol’yev O. A. Plyasunova A. G. Pokrovskii 《Russian Journal of Bioorganic Chemistry》2006,32(6):542-546
New 5′-phosphonates of 3′-azido-3′-deoxythymidine were synthesized and shown to be low-toxic and markedly active in MT-4 cell cultures infected with HIV-1. 相似文献
4.
Nucleoside H-Phosphonates. IX. Possible Side-Reactions During Hydrogen Phosphonate Diester Formation
Tor Regberg Jacek Stawinski Roger Ströberg 《Nucleosides, nucleotides & nucleic acids》2013,32(1):23-35
Abstract Possible side-reactions during hydrogenphosphonate diester formation in the presence of various condensing reagents (e.g. arensulfonyl derivatives, chlorophosphates and acyl chlorides) have been investigated using 31P NMR spectroscopy. 相似文献
5.
IS630/Tc1/mariner elements are diverse and widespread within insects. The African malaria mosquito, Anopheles gambiae, contains over 30 families of IS630/Tc1/mariner elements although few have been studied in any detail. To examine the history of Topi elements in An. gambiae populations, Topi elements (n=73) were sampled from five distinct populations of An. gambiae from eastern and western Africa and evaluated with respect to copy number, nucleotide diversity and insertion site-occupancy frequency. Topi 1 and 2 elements were abundant (10-34 per diploid genome) and highly diverse (pi=0.051). Elements from mosquitoes collected in Nigeria were Topi 2 elements and those from mosquitoes collected in Mozambique were Topi 1 elements. Of the 49 Topi transposase open reading frames sequenced none were found to be identical. Intact elements with complete transposase open reading frames were common, although based on insertion site-occupancy frequency data it appeared that genetic drift was the major force acting on these IS630/Tc1/mariner-type elements. Topi 3 elements were not recovered from any of the populations sampled in this study and appear to be rare elements in An. gambiae, possibly due to a recent introduction. 相似文献
6.
Chikako Murakami Takayuki Yamazaki Shinya Hanashima Shunya Takahashi Masaharu Takemura Shonen Yoshida Keisuke Ohta Hiromi Yoshida Fumio Sugawara Kengo Sakaguchi Yoshiyuki Mizushina 《Biochimica et Biophysica Acta - Proteins and Proteomics》2003,1645(1):72-80
Sulfo-glycolipids in the class of sulfoquinovosyl diacylglycerol (SQDG) including the stereoisomers are potent inhibitors of DNA polymerase α and β. However, since the α-configuration of SQDG with two stearic acids (α-SQDG-C18) can hardly penetrate cells, it has no cytotoxic effect. We tried and succeeded in making a permeable form, sulfoquinovosyl monoacylglycerol with a stearic acid (α-SQMG-C18) from α-SQDG-C18 by hydrolysis with a pancreatic lipase. α-SQMG-C18 inhibited DNA polymerase activity and was found to be a potent inhibitor of the growth of NUGC-3 cancer cells. α-SQMG-C18 arrested the cell cycle at the G1 phase, and subsequently induced severe apoptosis. The arrest was correlated with an increased expression of p53 and cyclin E, indicating that α-SQMG-C18 induced cell death through a p53-dependent apoptotic pathway. 相似文献
7.
D.?V.?YanvarevEmail author E.?A.?Shirokova Yu.?S.?Skoblov 《Russian Journal of Bioorganic Chemistry》2005,31(4):357-361
The kinetics of 3′-azido-3′-deoxythymidine phosphorylation with [32P]orthophosphoric acid was studied in the presence of various coupling agents. The most effective method, with the use of BrCN, provided the isolation of the target 3′-azido-3′-deoxythymidine 5′-[32P]monophosphate in 46% yield and with high specific radioactivity (>100 Ci/mmol).__________Translated from Bioorganicheskaya Khimiya, Vol. 31, No. 4, 2005, pp. 399–403.Original Russian Text Copyright © 2005 by Yanvarev, Shirokova, Skoblov. 相似文献
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9.
M. Todd Washington Karissa D. Carlson Bret D. Freudenthal John M. Pryor 《Biochimica et Biophysica Acta - Proteins and Proteomics》2010,1804(5):1113-1123
Most classical DNA polymerases, which function in normal DNA replication and repair, are unable to synthesize DNA opposite damage in the template strand. Thus in order to replicate through sites of DNA damage, cells are equipped with a variety of nonclassical DNA polymerases. These nonclassical polymerases differ from their classical counterparts in at least two important respects. First, nonclassical polymerases are able to efficiently incorporate nucleotides opposite DNA lesions while classical polymerases are generally not. Second, nonclassical polymerases synthesize DNA with a substantially lower fidelity than do classical polymerases. Many nonclassical polymerases are members of the Y-family of DNA polymerases, and this article focuses on the mechanisms of the four eukaryotic members of this family: polymerase eta, polymerase kappa, polymerase iota, and the Rev1 protein. We discuss the mechanisms of these enzymes at the kinetic and structural levels with a particular emphasis on how they accommodate damaged DNA substrates. Work over the last decade has shown that the mechanisms of these nonclassical polymerases are fascinating variations of the mechanism of the classical polymerases. The mechanisms of polymerases eta and kappa represent rather minor variations, while the mechanisms of polymerase iota and the Rev1 protein represent rather major variations. These minor and major variations all accomplish the same goal: they allow the nonclassical polymerases to circumvent the problems posed by the template DNA lesion. 相似文献
10.
Gurke S Barroso JF Hodneland E Bukoreshtliev NV Schlicker O Gerdes HH 《Experimental cell research》2008,314(20):3669-3683
Tunneling nanotube (TNT)-like structures are intercellular membranous bridges that mediate the transfer of various cellular components including endocytic organelles. To gain further insight into the magnitude and mechanism of organelle transfer, we performed quantitative studies on the exchange of fluorescently labeled endocytic structures between normal rat kidney (NRK) cells. This revealed a linear increase in both the number of cells receiving organelles and the amount of transferred organelles per cell over time. The intercellular transfer of organelles was unidirectional, independent of extracellular diffusion, and sensitive to shearing force. In addition, during a block of endocytosis, a significant amount of transfer sustained. Fluorescence microscopy revealed TNT-like bridges between NRK cells containing F-actin but no microtubules. Depolymerization of F-actin led to the disappearance of TNT and a strong inhibition of organelle exchange. Partial ATP depletion did not affect the number of TNT but strongly reduced organelle transfer. Interestingly, the myosin II specific inhibitor S-(−)-blebbistatin strongly induced both organelle transfer and the number of TNT, while the general myosin inhibitor 2,3-butanedione monoxime induced the number of TNT but significantly inhibited transfer. Taken together, our data indicate a frequent and continuous exchange of endocytic organelles between cells via TNT by an actomyosin-dependent mechanism. 相似文献