Enzyme rna

Luận án Tiến sĩ Y học "Nghiên cứu sự biến đổi nồng độ HBV-RNA và mối liên quan với HBEAG, HBV-DNA ở bệnh nhân viêm gan virus B mạn tính điều trị bằng Tenofovir Disoproxil Fumarat" trình bày các nội dung chính sau: Xác định sự biến đổi nồng độ HBV-RNA huyết tương ở bệnh nhân viêm gan virus B mạn tính được điều trị bằng Tenofovir Disoproxil Fumarate; Đánh giá mối liên quan giữa nồng độ HBV-RNA huyết tương với sự thay đổi của HBV-DNA và HBeAg ở bệnh nhân viêm gan virus B mạn tính được điều trị bằng Tenofovir Disoproxil Fumarate.

170p vigojek 02-02-2024 9 3   Download

Tách RNA tổng số RNA được tiến hành chiết tách gồm các bước cơ bản tương tự như DNA (bao gồm phá vỡ màng tế bào, loại protein, tủa RNA) nhưng ở đây ta dùng enzyme desoxyribonuclease (DNase) để phân huỷ DNA. Do RNA kém bền và dể bị phân huỷ bởi enzyme ribonuclease (RNase) có nhiều ở khắp nơi, hoạt tính cao lại bền với nhiệt (trên 90°C), vì vậy, điều kiện thao tác để chiết tách phải được tiến hành trong môi trường vô cùng nghiêm ngặt. ...

6p butmaulam 23-09-2013 194 34   Download

Enzyme sao chép một axit nucleic: Quá trình sao chép chuỗi axit nucleic tức là tổng hợp một chuỗi DNA hoặc RNA được tiến hành theo nguyên tắc bổ sung và đối song song. Việc thêm một nucleotide mới được tiến hành theo hướng 5’ → 3’. 1- Enzyme sao chép DNA → DNA Là các enzyme DNA-polymerase I, enzyme T4 DNA-polymerase, Taq polymerase tổng hợp chuỗi DNA từ một khuôn DNA hay còn gọi "enzyme phụ thuộc DNA".

5p butmaulam 23-09-2013 113 8   Download

Cơ chế: Phức hợp dsRNA gắn vào các đoạn RNA khóa mã → bất hoạt các RNA này → gen được biểu hiện Phức hợp dsRNA gắn vào promoter → dẫn dụ các enzyme tháo xoắn histone để khởi động sao mã

7p htc_12 13-05-2013 48 4   Download

The plastid transcription kinase (PTK), a component of the major RNA polymerase complex from mustard chloroplasts, has been implicated in redox-mediated regulation of plastid gene expression. A cloning strategy to define the PTK gene(s) resulted in the isolation of a full-length cDNA for a protein with overall high homology with the a subunit of cytosolic casein kinase (CK2) that contained an N-terminal extension for a putative plastid transit peptide.

9p system191 01-06-2013 45 4   Download

We report the cloning and functional charaterization of the full-length cDNA and gene encoding a Toxoplasma gondii DNA repair enzyme designated TgDRE. The gene is composed of three exons separated by two introns of 780 and 630 bp, and encodes a protein with a predicted molecular mass of 49.6 kDa. The native TgDRE protein, with a molecular mass of 60 kDa, is only detected in the virulent tachyzoite stage of T. gondii. However, the transcript is present in both asexual parasite stages, virulent tachyzoite and avirulent encysted bradyzoite. ...

9p research12 01-06-2013 33 5   Download

The efficacy of antiretroviral agents approved for the treat-ment of HIV-1 infection is limited by the virus’s ability to develop resistance. As such there is an urgent need for new ways of thinking about anti-HIV drug development, and accordingly novel viral and cellular targets critical toHIV-1 replication need to be explored and exploited. The retroviral RNA genome encodes for three enzymes essential for viral replication: HIV-1 protease (PR), HIV-1 reverse transcrip-tase (RT) and HIV-1 integrase (IN). ...

9p tumor12 22-04-2013 33 2   Download

Phosphorylation of RNA polymerase II’s largest subunit C-terminal domain (CTD) is a key event during mRNA metabolism. Numerous enzymes, including cell cycle-dependent kinases and TFIIF-dependent phosphatases tar-get the CTD. However, the repetitive nature of the CTD prevents determination of phosphorylated sites by conven-tional biochemistry methods. Fortunately, a panel of monoclonal antibodies is available that distinguishes between phosphorylated isoforms of RNA polymerase II’s (RNAP II) largest subunit....

12p tumor12 20-04-2013 49 2   Download

The HeLa cell terminal uridylyltransferase (TUTase) that specifically modifies the 3¢-end of mammalian U6 small nuclear RNA (snRNA) was characterized with respect to ionic dependence and substrate requirements. Optimal enzyme activity was obtained at moderate ionic strength (60 mMKCl) anddependedon thepresenceof 5 mMMgCl2. In vitrosynthesizedU6 snRNA without a 3¢-terminal UMP residue was not accepted as substrate.

10p tumor12 20-04-2013 40 3   Download

The dimeric structure of seminal ribonuclease (BS-RNase) is maintained by noncovalent interactions and by two intersubunit disulfide bridges.Another unusual feature of this enzyme is its antitumour action, consisting in a cyto-toxic activity selective for malignant cells.This cytotoxic action is exerted when the protein reaches the cytosol of the affected cells, where it degrades ribosomal RNA, thus blocking protein synthesis and leading cells to death.

8p fptmusic 16-04-2013 37 2   Download

A search has been initiated for lead inhibitors of the non-structural protein 3 (NS3)-associated NTPase/helicase activities of hepatitis C virus,the related West Nile virus, Japanese encephalitis virus and the human mitochondrial Suv3 enzyme. Random screening of a broad range of unre-lated low-molecular mass compounds,employing both RNA and DNA substrates, revealed that 4,5,6,7-tetra-bromobenzotriazole (TBBT) hitherto known as a potent highly selective inhibitor of protein kinase 2,is a good inhibitor of the helicase,but not NTPase,activity of hepa-titis C virus NTPase/helicase. ...

9p fptmusic 16-04-2013 41 4   Download

Promoter là một thành phần quan trọng trong cấu trúc của tất cả các gen và đóng vai trò then chốt trong việc biểu hiện gen. Từ những nghiên cứu mở đầu về promoter tren vi khuẩn vào cuối những năm 70, đến nay, nhiều promoter từ các gen ở nhiều loài khác nhau đã được phân lập, xác định các vùng chức năng.

19p tuyetmuadong2013 15-04-2013 120 16   Download

Classical swine fever virus nonstructural protein 5B (NS5B) encodes an RNA-dependent RNA polymerase, a key enzyme of the viral replication complex. To better under-stand the initiation of viral RNA synthesis and to establish anin vitroreplication system, a recombinant NS5B protein, lacking the C-terminal 24-amino acid hydrophobic domain, was expressed inEscherichia coli.

10p fptmusic 12-04-2013 47 4   Download

TheSCO2299gene fromStreptomyces coelicolorencodes a single peptide consisting of 497 amino acid residues. Its N-terminal region shows high amino acid sequence similarity to RNase HI, whereas its C-terminal region bears similarity to the CobC protein, which is involved in the synthesis of cobalamin. The SCO2299gene suppressed a temperature-sensitive growth defect of anEscherichia coliRNase H-deficient strain, and the recombinant SCO2299 protein cleaved an RNA strand of RNAÆDNA hybridin vitro.

0p awards 06-04-2013 42 1   Download

Exoribonuclease II (RNase II), encoded by thernb gene, is a ubiquitous enzyme that is responsible for 90% of the hydrolytic activity in Escherichia colicrude extracts. The E. colistrain SK4803, carrying the mutant allelernb296, has been widely used in the study of the role of RNase II. We determined the DNA sequence ofrnb296 and cloned this mutant gene in an expression vector. Only a point mutation in the coding sequence of the gene was detected, which results in the single substitution of aspartate 209 for asparagine....

0p awards 05-04-2013 42 2   Download

BacterialRNApolymerase (RNAP) is the central enzyme of gene expression that is responsible for the synthesis of all types of cellular RNAs. The process of transcription is accompanied by complex structural rearrangements of RNAP. Despite the recent progress in structural studies of RNAP, detailed mechanisms of conformational changes of RNAP that occur at different stages of transcription remain unknown.

11p awards 05-04-2013 42 2   Download

We purified pancreatic deoxyribonuclease I (DNase I) from the shark Heterodontus japonicususing three-step column chromatography. Although its enzymatic properties resem-bled those of other vertebrateDNases I, sharkDNase I was unique inbeingabasicprotein.Full-lengthcDNAs encoding theDNases I of two shark species,H. japonicusandTriakis scyllia, were constructed from their total pancreatic RNAs using RACE.

8p awards 05-04-2013 47 4   Download

GE23077, a novel microbial metabolite recently isolated from Actinomadurasp. culture media, is a potent and selective inhibitor of bacterial RNApolymerase (RNAP). It inhibitsGram-positive (Bacillus subtilis) andGram-negative (Escherichia coli)RNAPs with IC50 values (i.e. the concen-tration at which the enzyme activity is inhibited by 50%) in the 10 )8 Mrange, whereas it is not active onE. coliDNA polymerase or on eukaryotic (wheat germ) RNAP II (IC50 values10 )4 Min both cases).

0p awards 05-04-2013 56 2   Download

Ribonuclease L (RNase L) is a key enzyme in the 2-5A host defense system, and its activity is strictly regulated by an unusual 2¢,5¢-linked oligoadenylate (2-5A).A bipartite model, in which the N-terminal half of RNase L is responsible for the 2-5A binding and the C-terminal half alone is able to hydrolyse the substrate RNA, has been proposed on the basis of the results of deletion mutant analyses [Dong, B.& Silverman, R.H.

8p dell39 03-04-2013 27 4   Download

Ribonuclease H1 (RNase H1) is a widespread enzyme found in a range of organisms from viruses to humans. It is capable of degrading the RNA moiety of DNA–RNA hybrids and requires a bivalent ion for activity. In contrast with most eukaryotes, which have one gene encoding RNase H1, the activity of which depends on Mg 2+ ions, Caenorhabditis eleganshas four RNase H1-related genes, and one of them has an isoform produced by alter-native splicing.

10p dell39 27-03-2013 40 3   Download