Macaya R F, Schultze P, Smith F W, Roe J A, Feigon J
Department of Chemistry and Biochemistry, University of California, Los Angeles 90024.
Proc Natl Acad Sci U S A. 1993 Apr 15;90(8):3745-9. doi: 10.1073/pnas.90.8.3745.
We have used two-dimensional 1H NMR spectroscopy to study the conformation of the thrombin-binding aptamer d(GGTTGGTGTGGTTGG) in solution. This is one of a series of thrombin-binding DNA aptamers with a consensus 15-base sequence that was recently isolated and shown to inhibit thrombin-catalyzed fibrin clot formation in vitro [Bock, L. C., Griffin, L. C., Latham, J. A., Vermaas, E. H. & Toole, J. J. (1992) Nature (London) 355, 564-566]. The oligonucleotide forms a unimolecular DNA quadruplex consisting of two G-quartets connected by two TT loops and one TGT loop. A potential T.T bp is formed between the two TT loops across the diagonal of the top G-quartet. Thus, all of the invariant bases in the consensus sequence are base-paired. This aptamer structure was determined by NMR and illustrates that this molecule forms a specific folded structure. Knowledge of this structure may be used in the further development of oligonucleotide-based thrombin inhibitors.
我们已使用二维¹H核磁共振光谱法来研究凝血酶结合适体d(GGTTGGTGTGGTTGG)在溶液中的构象。这是一系列具有15个碱基共有序列的凝血酶结合DNA适体之一，该序列最近被分离出来，并显示在体外可抑制凝血酶催化的纤维蛋白凝块形成[博克，L.C.，格里芬，L.C.，莱瑟姆，J.A.，弗尔马斯，E.H.和图尔，J.J.（1992年）《自然》（伦敦）355, 564 - 566]。该寡核苷酸形成一个单分子DNA四链体，由两个G - 四联体通过两个TT环和一个TGT环连接而成。在顶部G - 四联体对角线上的两个TT环之间形成了一个潜在的T·T碱基对。因此，共有序列中所有的不变碱基都形成了碱基对。这种适体结构是通过核磁共振确定的，表明该分子形成了一种特定的折叠结构。这一结构的知识可用于基于寡核苷酸的凝血酶抑制剂的进一步开发。
