Dissecting the contribution of thrombin exosite I in the recognition of thrombin binding aptamer
Dissecting the contribution of thrombin exosite I in the recognition of thrombin binding aptamer
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DOI：
10.1111/febs.12561
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发表时间：
2013-12-01
期刊：
影响因子：
5.4
通讯作者：
Sica, Filomena
中科院分区：
文献类型：
--
作者：
Pica, Andrea;Russo Krauss, Irene;Sica, Filomena
凝血酶在凝血级联反应中起着关键作用;因此，它代表了治疗几种血液疾病的主要靶点。15-mer DNA寡核苷酸5-GGTTGGTGTGGTTGG-3，称为凝血酶结合适体（TBA），是该酶的高效抑制剂。TBA折叠为反平行的椅状G-四链体结构，其中两个G-四链体在一侧被两个TT环包围，在相对侧被一个TGT环包围。以前的晶体学研究表明，TBA通过其TT环T3 T4和T12 T13结合凝血酶外位点I。为了更好地了解凝血酶-TBA相互作用，我们对凝血酶与两个TBA突变体TBAT 3和TBAT 12之间的复合物进行了晶体学表征，这两个突变体分别缺乏T3和T12的核碱基。这两个复合物的结构细节表明，exosite I实际上分为两个区域，这两个区域对TBA识别的贡献不同。这些结果为更合理地设计具有改善的治疗作用的新适体提供了基础。
Thrombin plays a pivotal role in the coagulation cascade; therefore, it represents a primary target in the treatment of several blood diseases. The 15-mer DNA oligonucleotide 5-GGTTGGTGTGGTTGG-3, known as thrombin binding aptamer (TBA), is a highly potent inhibitor of the enzyme. TBA folds as an antiparallel chair-like G-quadruplex structure, with two G-tetrads surrounded by two TT loops on one side and a TGT loop on the opposite side. Previous crystallographic studies have shown that TBA binds thrombin exosite I by its TT loops, T3T4 and T12T13. In order to get a better understanding of the thrombin-TBA interaction, we have undertaken a crystallographic characterization of the complexes between thrombin and two TBA mutants, TBAT3 and TBAT12, which lack the nucleobase of T3 and T12, respectively. The structural details of the two complexes show that exosite I is actually split into two regions, which contribute differently to TBA recognition. These results provide the basis for a more rational design of new aptamers with improved therapeutic action.