Kelly J A, Feigon J, Yeates T O
Department of Chemistry and Biochemistry, University of California, Los Angeles 90095-1570, USA.
J Mol Biol. 1996 Mar 1;256(3):417-22. doi: 10.1006/jmbi.1996.0097.
The thrombin-binding aptamer d(GGTTGGTGTGGTTGG) is one of a family of DNA oligonucleotides that were identified by in vitro selection to bind specifically and with high affinity to thrombin. Two groups independently determined the tertiary structure in solution by NMR and at about the same time, the X-ray crystal structure of the aptamer in complex with thrombin was reported. In all cases, the thrombin-binding aptamer was found to fold into a structure containing two planar guanine quartets as its core. The NMR and crystal structures, however, have fundamentally different folding patterns owing to differences in the way these central bases are connected. We discuss the distinctions between the refined crystal and solution structures and show that the NMR model is consistent with the X-ray diffraction data.
凝血酶结合适体d(GGTTGGTGTGGTTGG)是通过体外筛选鉴定出的一类DNA寡核苷酸之一，它能特异性且高亲和力地结合凝血酶。两组研究人员分别通过核磁共振（NMR）独立测定了该适体在溶液中的三级结构，并且大约在同一时间，有报道称该适体与凝血酶复合物的X射线晶体结构。在所有情况下，均发现凝血酶结合适体折叠成以两个平面鸟嘌呤四联体为核心的结构。然而，由于这些中心碱基连接方式的差异，NMR和晶体结构具有根本不同的折叠模式。我们讨论了精细的晶体结构和溶液结构之间的差异，并表明NMR模型与X射线衍射数据一致。
