Ferré-D'amaré A R, Rupert P B
Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue N., Seattle, WA 98109-1024, USA.
Biochem Soc Trans. 2002 Nov;30(Pt 6):1105-9. doi: 10.1042/bst0301105.
The hairpin ribozyme is one of four known natural catalytic RNAs that carry out sequence-specific cleavage of RNA. It is of particular biochemical interest because, unlike 'classic' ribozymes, such as the group I intron, it appears not to employ metal ions as catalytic cofactors. We have determined the crystal structure of a hairpin-ribozyme-inhibitor complex at a resolution of 2.4 A. The active site of the ribozyme results from docking of two irregular double helices. Docking results in major structural rearrangements of the helices, including a distortion of the substrate strand that brings it into a reactive conformation. It remains to be established whether this RNA enzyme relies exclusively on binding energy to carry out catalysis, or whether some other mechanism, such as general acid-base catalysis, is being employed.
发夹状核酶是已知的四种天然催化RNA之一，可对RNA进行序列特异性切割。它具有特殊的生化意义，因为与“经典”核酶（如I类内含子）不同，它似乎不使用金属离子作为催化辅因子。我们已确定了一种发夹状核酶-抑制剂复合物的晶体结构，分辨率为2.4埃。核酶的活性位点由两个不规则双螺旋对接形成。对接导致螺旋发生重大结构重排，包括底物链的扭曲，使其进入反应构象。这种RNA酶是仅依靠结合能进行催化，还是采用了其他机制（如一般酸碱催化），仍有待确定。
