title: Studies on the effect of thymine-mercury-thymine stem as a structural or functional motif in DNAzymes.
abstract: T-Hg-T base pair formation has been demonstrated to be compatible with duplex DNA context, with considerable thermal stability contribution. Here, the T-Hg-T stem in two small DNAzymes 8-17 and 10-23 was studied for its structural and functional roles. The recognition arm 5' to the cleavage site of 10-23 DNAzyme complex and the stem in the catalytic loop of 8-17 DNAzyme could be replaced by consecutive T-Hg-T stem of different length. The linear relationship between the activity of the complex 10-23DZ-6T+D19-6T and the concentration of Hg(2+) demonstrated that the T-Hg-T stem contributes thermal stability of the recognition arm binding. The effect of T-Hg-T stem in the catalytic core of 8-17 DNAzyme and the position-dependent effect in 10-23 DNAzyme demonstrated that T-Hg-T base pair is not compatible with canonical base pairs in playing the functions of nucleic acids.
authors.affiliation: a School of Pharmacological Sciences , Guangxi Medical University , 22 Shuangyong Road, Nanning , China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.forename: Gaofeng
authors.initials: G
authors.lastname: Liu
authors.forename: Zhiwen
authors.initials: Z
authors.lastname: Li
authors.forename: Wei
authors.initials: W
authors.lastname: Rong
authors.forename: Jianping
authors.initials: J
authors.lastname: Yu
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhou
authors.forename: Keliang
authors.initials: K
authors.lastname: Liu
authors.forename: Zhibing
authors.initials: Z
authors.lastname: Zheng
authors.forename: Junlin
authors.initials: J
authors.lastname: He
mesh_terms: D020029:Base Pairing; D004247:DNA / Q000737:chemistry; D021881:DNA, Catalytic / Q000737:chemistry*; D004277:DNA, Single-Stranded / Q000737:chemistry*; D008628:Mercury / Q000737:chemistry*; D059367:RNA Cleavage; D013816:Thermodynamics; D013941:Thymine / Q000737:chemistry*
chemical_list: D021881:DNA, Catalytic; D004277:DNA, Single-Stranded; C402582:RNA-cleaving DNA 10-23; C407482:RNA-cleaving DNA 8-17; D004247:DNA; D008628:Mercury; D013941:Thymine
keywords: DNAzyme; Thymine-mercury-thymine stem; cleavage activity