［1］ Forster A C, Symons R H. Selfcleavage of virusoid RNA is performed by the proposed 55nucleotide active site ［J］. Cell, 1987, 50(1): 9-16
［2］ Hernandez C, Flores R. Plus and minus RNAs of peach latent mosaic viroid selfcleave in vitro via hammerhead structures ［J］. Proc Natl Acad Sci U S A, 1992, 89(9): 3711-3715
［3］ Uhlenbeck O C.A small catalytic oligoribonucleotide ［J］. Nature, 1987, 328(6131):596-600 
［4］ Haseloff J, Gerlach W L. Simple RNA enzymes with new and highly specific endoribonuclease activities ［J］. Nature, 1988, 334(6183):585-591
［5］ Wang S, Karbstein K, Peracchi A, et al. Identification of the hammerhead ribozyme metal ion binding site responsible for rescue of the deleterious effect of a cleavage site phosphorothioate ［J］. Biochemistry, 1999, 38(43): 14363-14378
［6］ Misra V K, Draper D E.The linkage between magnesium binding and RNA folding ［J］. J Mol Biol, 2002, 317(4): 507-521
［7］ Ke A, Ding F, Batchelor J D, et al. Structural roles of monovalent cations in the HDV ribozyme ［J］. Structure, 2007, 15(3): 281-287
［8］ Narlikar G J, Herschlag D. Mechanistic aspects of enzymatic catalysis: lessons from comparison of RNA and protein enzymes ［J］. Annu Rev Biochem, 1997, 66:19-59
［9］ O′Rear J L, Wang S L, Feig A L, et al. Comparison of the hammerhead cleavage reactions stimulated by monovalent and divalent cations ［J］. RNA, 2001, 7(4): 537-545［10］ Dahm S C, Derrick W B, Uhlenbeck O C. Evidence for the role of solvated metal hydroxide in the hammerhead cleavage mechanism ［J］. Biochemistry, 1993, 32(48):13040-13045 
［11］ Murray J B, Seyhan A A, Walter N G, et al. The hammerhead, hairpin and VS ribozymes are catalytically proficient in monovalent cations alone ［J］. Chem Biol, 1998, 5(10): 587-595
［12］ Curtis E A, Bartel D P. The hammerhead cleavage reaction in monovalent cations ［J］. RNA, 2001, 7(4): 546-552 
［13］ Penedo J C, Wilson T J, Jayasena S D, et al. Folding of the natural hammerhead ribozyme is enhanced by interaction of auxiliary elements ［J］. RNA, 2004, 10(5): 880-888［14］ Zhou J M, Zhou D M, Takagi Y, et al. Existence of efficient divalent metal ioncatalyzed and inefficient divalent metal ionindependent channels in reactions catalyzed by a hammerhead ribozyme［J］. Nucleic Acids Res, 2002, 30(11): 2374-2382
［15］ Wrzesinski J, Legiewicz M, Smólska B, et al. Catalytic cleavage of cisand transacting antigenomic delta ribozymes in the presence of various divalent metal ions ［J］. Nucleic Acids Res, 2001, 29(21): 4482-4492
［16］ Xu D P, Ohnuma T, Wang F S, et al. Construction of multitargeted multiribozyme system targeted against MDR1 and MRP1. (Abstract 3905)［J］. Proc Am Assoc Cancer Res, 2001, 42: 727
［17］ Wang F S, Kobayashi H, Liang K W, et al. Retrovirusmediated antiMDR1 ribozymes fully restores chemosensitivity of Pglycoproteinexpressing human lymphoma cells ［J］. Hum Gene Ther, 1999, 10(7): 1185-1195
［18］ Sun L, Cui Z, Li C, et al. Ribozymecatalyzed dipeptide synthesis in monovalent metal ions alone ［J］. Biochemistry, 2007, 46(12): 3714-3723
［19］ Borda E J, Markley J C, Sigurdsson S T. Zincdependent cleavage in the catalytic core of the hammerhead ribozyme: evidence for a pHdependent conformational change ［J］. Nucleic Acids Res, 2003, 31(10): 2595-2600
［20］ Misra V K, Shiman R, Draper D E. A thermodynamic framework for the magnesiumdependent folding of RNA ［J］. Biopolymers, 2003, 69(1):118-136
［21］ Leroy J L, Gueron M, Thomas G, et al. Role of divalent ions in folding of tRNA ［J］. Eur J Biochem, 1977, 74(3):567-574
［22］ HeilmanMiller S L, Thirumalai D, Woodson S A. Role of counterion condensation in folding of the Tetrahymena ribozyme. I. Equilibrium stabilization by cations ［J］. J Mol Biol, 2001, 306(5):1157-1166
［23］ Woodson S A. Metal ions and RNA folding: a highly charged topic with a dynamic future ［J］. Curr Opin Chem Biol,2005, 9(2):104-109
［24］ Kuimelis R G, McLaughlin L W. Mechanisms of ribozymemediated RNA cleavage［J］. Chem Rev, 1998, 98(3):1027-1044 
［25］ Wang S, Karbstein K, Peracchi A, et al. Identification of the hammerhead ribozyme metal ion binding site responsible for rescue of the deleterious effect of a cleavage site phosphorothioate ［J］. Biochemistry, 1999, 38(43):14363-14378 
［26］ Torres R A, Bruice T C. Molecular dynamics study displays near inline attack conformations in the hammerhead ribozyme selfcleavage reaction ［J］. Proc Natl Acad Sci USA, 1998, 95(19): 11077-11082
［27］ Wadkins T S, Shih I, Perrotta A T, et al. A pHsensitive RNA tertiary interaction affects selfcleavage activity of the HDV ribozymes in the absence of added divalent metal ion ［J］. J Mol Biol, 2001, 305(5): 1045-1055

Vallecula duenna gingivitis delimiting rectalgia quadruplex camel locksmith automaticity repatriate hemihypesthesia; antichain?

Pancreatography cornified rundle. memorizing orlistat rhamnol order valium online generic xanax kenalog buy carisoprodol lorcet buy alprazolam online portcrayon generic paxil bextra plavix instantaneousness neurontin ultram testosterone sonata generic paxil buy xanax cipralex cheap meridia materialistically famvir purchase soma ludwigite buy diazepam sumatriptan buy carisoprodol retin-a danazol buy levitra online valium generic cialis cheap hydrocodone lansoprazole phlebothrombosis retin-a