Chen S M, Leupin W, Chazin W J
Department of Molecular Biology, Research Institute of Scripps Clinic, La Jolla, CA 92037.
Int J Biol Macromol. 1992 Feb;14(1):57-63. doi: 10.1016/s0141-8130(05)80021-2.
A variety of two-dimensional nuclear magnetic resonance (n.m.r.) techniques were utilized for structural studies of the dodecadeoxy-nucleotide duplex d-(CCAAAAATTTCC).d-(GGAAATTTTTGG). Overall, the duplex was found to adopt a conformation of the B-DNA type. Direct measurement of 1H-1H coupling constants of the deoxyribose rings and comparison of nuclear Overhauser effects (NOEs) involving characteristic intra- and inter-nucleotide proton-proton connectivities indicate that the sugar rings are all in predominantly C2'-endo/S-type conformation. The appearance of NOEs between adenine 2H and sugar l'H resonances indicates a narrowing of the minor groove at the 3' end of the (dA)n tracts. Several lines of evidence indicate that a conformational change in the DNA duplex is introduced by the (dA)5 tract, in support of the junction model for curved DNA. The results are compared with previous structural studies of the evidence for curvature in duplex DNA containing (dA)n tracts.
利用多种二维核磁共振（n.m.r.）技术对十二脱氧核苷酸双链体d-(CCAAAAATTTCC).d-(GGAAATTTTTGG)进行结构研究。总体而言，发现该双链体呈现B-DNA型构象。对脱氧核糖环的1H-1H耦合常数进行直接测量，并比较涉及核苷酸内和核苷酸间特征性质子-质子连接性的核Overhauser效应（NOEs），结果表明糖环主要处于C2'-内向/S型构象。腺嘌呤2H与糖1'H共振之间出现的NOEs表明(dA)n片段3'端小沟变窄。多条证据表明，(dA)5片段会导致DNA双链体发生构象变化，这支持了弯曲DNA的连接模型。将这些结果与之前关于含(dA)n片段的双链DNA中曲率证据的结构研究进行了比较。
