事实上,除右手双螺旋结构外,还存在其他非经典DNA构象,如三链体DNA(triplex DNA)。三链体DNA是由单链DNA通过胡斯坦氢键(Hoogsteen hydrogen bonds)与双链DNA的大沟特异性结合形成的一种三链结构【2】。该结构在基因组中广泛分布,发挥重要的基因调控作用,并可导致基因组不稳定性。基于以上功能,三链体形成寡核苷酸(...
structure resembling a ladder twisted into a spiral, called adouble helix.Each rung is made up of two chemical bases, callednucleotides,that are joined together by hydrogen bonds. There are four kinds of nucleotides in a DNA molecule: cytosine, guanine, adenine, and thymine—C, G, A, and ...
质粒作为微生物中存在特殊DNA形式,其在闭环状态下会形成超螺旋结构,其中就会存在H型DNA,在一条互补的B型双螺旋的基础上,第三链依然以互补的形式,依靠Hoogsteen型氢键 (Hoogsteen-type hydrogen bonds),结合到原有双螺旋的嘌呤上,以T•A•T 或者C•G•C+三飞的形式形成三螺旋。 但这种结构目前发现于大肠杆...
事实上,除右手双螺旋结构外,还存在其他非经典DNA构象,如三链体DNA(triplex DNA)。三链体DNA是由单链DNA通过胡斯坦氢键(Hoogsteen hydrogen bonds)与双链DNA的大沟特异性结合形成的一种三链结构【2】。该结构在基因组中广泛分布,发挥...
(suggested by Chargaff’s Rules). Thus, adenine and thymine are complementary base pairs, and cytosine and guanine are also complementary base pairs. The base pairs are stabilized by hydrogen bonds:adenine and thymine form two hydrogen bonds and cytosine and guanine form three hydrogen bonds.The ...
bondsbetween the phosphate of onenucleotideand the sugar of the next, forming a phosphate-sugarbackbonefrom which the nitrogenous bases protrude. One strand is held to another byhydrogen bondsbetween the bases; the sequencing of this bonding is specific—i.e., adenine bonds only with thymine, ...
The specificity of triplexes relies in the formation of Hoogsteen hydrogen bonds between the third-strand bases and the purine bases of the duplex (Rajagopal and Feigon, 1989b; Soyfer and Potaman, 1996; Thuong and Hélène, 1993). Triplexes can be classified based on the composition and ...
bonds calledhydrogen bonds. This base-to-base bonding is not random; rather, each A in one strand always pairs with a T in the other strand, and each C always pairs with a G. The double-stranded DNA that results from this pattern of bonding looks much like a ladder with sugar-...
The bases on each strand are joined to the bases on the other strand with hydrogen bonds, but different bases have different chemical structures. Cytosine and thymine (and uracil in RNA) are pyrimidines, containing one ring. Adenine and guanine are purines, containing two rings. The pyrimidine...
The bases of each strand link together viahydrogen bonds. Adenine and Guanine are purines as they have two rings in their molecular structure. Thymine and Cytosine are pyrimidines as they only have one ring in their molecular structure. A purine will link with a pyrimidine. Adenine and thymine...