Cytosine

Luận văn thạc sĩ Vật lý với đề tài "Theo dõi quá trình tautome dạng imino-amino của cytosine bằng xung laser siêu ngắn" trình bày nội dung sau: cơ sở lý thuyết và phương pháp tính toán, chuyển động hạt nhân hydro và quá trình tautome dạng imino-amino, phản xạ sóng hài bậc cao của cytosine và dấu vết quá trình tautome.

113p hoydinha_hoihoidi 22-12-2014 127 16   Download

Năm 1991, một nhóm các nhà khoa học đứng đầu là MacLennan đã xác định đƣợc trình tự gen halothan (Fujii và ctv, 1991). Ở heo, gen halothan nằm trên nhiễm sắc thể số 6, gồm 2 alen: N và n, tạo nên 3 kiểu gen NN, Nn và nn. Theo MacLennan và cộng sự, gen đột biến lặn n là kết quả của sự đột biến C-cytosin thành T-thymin ở vị trí base 1843 của gen mã hóa thụ thể ryanodin (ryr-1), thụ thể này nằm trong kênh phóng thích canxi của lƣới nội bào ở tế bào cơ...

76p canhchuon_1 21-06-2013 156 21   Download

The Sp family is a family of transcription factors that bind to cis-elements in the promoter regions of various genes. Regulation of transcription by Sp proteins is based on interactions between a GC-rich binding site (GGGCGG) in DNA and C-terminal zinc finger motifs in the proteins. In this study, we characterized the GC-rich promoter of the gene for the DNA methyltransferase (Dnmt1) that is responsible for methylation of cytosine residues in mammals and plays a role in gene silencing.

10p system191 01-06-2013 38 4   Download

Recently, we have identified and purified minisatellite DNA binding proteins (MNBPs) that bind to the mouse hypervariable minisatellite Pc-1, from NIH3T3 cells. This study describes the isolation and characterization of a mouse leucine-rich protein (mLRP130) as one of the MNBPs that binds to the C-rich strand of Pc-1. The mLRP130 cDNA was demonstrated to encode a polypeptide of 1306 aminoacid residues with a deduced molecular mass of 137 kDa, and the mLRP130 mRNA is detected in various organs, including heart, brain, liver, skeletal muscle, kidneys and testes.

7p system191 01-06-2013 25 4   Download

DNA cytosine methyltransferaseMspI(M.MspI) must require a different type of interaction of protein with DNA from other bacterial DNA cytosine methyltransferases (m5C-MTases) to evoke the topoisomerase activity that it possesses in addition toDNA-methylation ability. Thismay require a different structural organization in the solution phase from the reported consensus structural arrangement for m5C-MTases.

7p research12 29-04-2013 47 3   Download

Populations in Southeast AsiaandSouthChinahave highfrequencies ofa-thalassemia caused by a-globin gene mutations and/or deletions. This study was designed to find an efficient and simple diagnostic test for the mutations and deletions. A duplex polymerase chain reaction (PCR)/denaturing high-pressure liquid chromatography (DHPLC) was used to detect the mutations and deletions. A blinded study of 110 samples, which included 92 a-thalassemia samples with various genotypes and 18 normal DNA samples, was carried out by the methods.

8p zingzing09 24-04-2013 70 2   Download

The availability of a system for the functional expression of genes coding formolybdenumhydroxylases is a prerequisite for the construction of enzyme variants bymutagenesis. For the expression cloning of quinoline 2-oxidoreductase (Qor) fromPseudomonas putida86 – that contains the molybdo-pterin cytosine dinucleotide molybdenum cofactor (Mo-MCD), two distinct [2Fe)2S] clusters and FAD – the qorMSLgenes were inserted into the broad host range vector, pJB653, generating pUF1.P. putidaKT2440 and P. putida86-1Dqor were used as recipients for pUF1....

11p tumor12 20-04-2013 56 5   Download

EcoRII DNA methyltransferase (M.EcoRII) recognizes the 5¢…CC*T/AGG…3¢ DNA sequence and catalyzes the transfer of the methyl group fromS-adenosyl-L-methionine to the C5 position of the inner cytosine residue (C*). Here, we study themechanismof inhibitionofM.EcoRII byDNA containing 2-pyrimidinone, a cytosine analogue lacking an NH2 group at the C4 position of the pyrimidine ring. Also, DNA containing 2-pyrimidinone was used for probing contacts ofM.EcoRII with functional groups of pyrimidine bases of the recognition sequence....

9p dell39 03-04-2013 35 4   Download

This work reports on the direct electrochemistry of the Desulfovibrio gigasaldehyde oxidoreductase (DgAOR), a molybdenum enzyme of the xanthine oxidase family that contains three redox-active cofactors: two [2Fe-2S] centers and a molybdopterin cytosine dinucleotide cofactor. The voltammetric behavior of the enzyme was analyzed at gold and carbon (pyrolytic graphite and glassy carbon) elec-trodes. Two different strategies were used: one with the molecules confined to the electrode surface and a second withDgAOR in solution....

10p dell39 03-04-2013 41 4   Download

Anti-poxvirus therapies are currently limited to cidofovir [(S)-1-(3-hydroxy-2-phosphonylmethoxypropyl)cytosine], but drug-resistant strains have already been characterized. In the aim of finding a new target, the thymidy-late (TMP) kinase from vaccinia virus, the prototype of Orthopoxvirus, has been overexpressed inEscherichia coliafter cloning the gene (A48R).

12p dell39 27-03-2013 39 4   Download

281. Base nitơ trong thành phần acid nucleic dẫn xuất từ nhân: A. Purin, Pyridin B. Purin, Pyrol C. Pyrimidin, Imidazol D. Pyridin, Indol E. Pyrimidin, Purin 282. Base nitơ dẫn xuất từ pyrimidin: A. Cytosin, Uracil, Histidin B. Uracil, Cytosin, Thymin C. Thymin, Uracil, Guanin D. Uracil, guanin, Hypoxanthin E. Cytosin, Guanin, Adenin

16p m310dy1ndark 05-03-2013 282 16   Download

DNA methylation is an important mechanism involved in embryogenesis and tumor development. Changing cytosines to 5-methylcytosines in CpG dinucleotides has been found to be responsible for the inactivation of tumor suppressor genes by repressing transcription.

15p media19 04-03-2013 36 2   Download

Cytosine methylation at the 5-carbon position is the only known stable base modification found in the mammalian genome. The organization and modification of chromatin is a key factor in programming gene expression patterns. Recent findings suggest that DNA methylation at the junction of transcription initiation and elongation plays a critical role in suppression of transcription.

22p vinaphone15 28-02-2013 40 3   Download

Human 8-oxoguanine-DNA glycosylase (OGG1) efficiently removes muta-genic 8-oxo-7,8-dihydroguanine (8-oxoGua) and 2,6-diamino-4-hydroxy-5-formamidopyrimidine when paired with cytosine in oxidatively damaged DNA. Excision of 8-oxoGua mispaired with adenine may lead to GfiT transversions.

14p vinaphone15 25-02-2013 41 3   Download

The DNA of every cell in the body carries a pattern of chemical modifications due to the methylation of cytosine in the dinucleo-tide sequence 5¢CG. It is thought that these chemical marks help to define the pattern of gene expression that is appropriate for each cell type.

80p viettel02 22-02-2013 44 4   Download

Three DNA regions carrying genes encoding putative homologs of xanthine dehydrogenases were identified inEscherichia coli, named xdhABC, xdhD, andyagTSRQ. Here, we describe the purification and characterization of gene products of the yagTSRQ operon, a molybdenum-containing iron– sulfur flavoprotein from E. coli, which is located in the periplasm.

13p viettel02 22-02-2013 17 3   Download

DNA methylation affects important developmental processes in both plants and animals. The process of methylation of cytosines at C-5 is catalysed by DNA methyltransferases (MTases), which are highly conserved, both struc-turally and functionally, in eukaryotes. In this study, we identified and characterized cytosine DNA MTase genes that are activated with the onset of reproductive development in rice.

11p viettel02 20-02-2013 47 5   Download

Mammalian intracellular ribonuclease L (RNase L) is a latent endoribo-nuclease that functions against viral infections as an apoptosis-inducing protein, and its activity requires intracellular 5¢-end-triphosphorylated-2¢,5¢ oligoadenylates (2-5A) as an activator. Previously, we showed that RNase L can be activated in human cancer cell line HT1080 by an RNA polymerase I inhibitor, 1-(3-C-ethynyl-b-d-ribo-pentofuranosyl)cytosine (3¢-ethynylcytidine; ECyd).

10p viettel02 19-02-2013 40 3   Download

CXXC finger protein 1 (Cfp1), encoded by theCXXC1gene, is a compo-nent of the euchromatic Setd1A histone H3K4 methyltransferase complex, and is a critical regulator of histone methylation, cytosine methylation, cel-lular differentiation, and vertebrate development.

13p mobifone23 18-01-2013 44 3   Download

The Dnmt3a DNA methyltransferase is responsible for establishing DNA methylation patterns during mammalian development. We show here that the mouse Dnmt3a DNA methyltransferase is able to transfer the methyl group fromS-adenosyl-L-methionine (AdoMet) to a cysteine residue in its catalytic center. This reaction is irreversible and relatively slow.

9p cosis54 05-01-2013 44 6   Download