Lafontaine D A, Norman D G, Lilley D M
Cancer Research U.K. Nucleic Acid Structure Research Group, Department of Biochemistry, MSI/WTB Complex, The University of Dundee, UK.
Biochem Soc Trans. 2002 Nov;30(Pt 6):1170-5. doi: 10.1042/bst0301170.
The Varkud satellite ribozyme is the largest of the small nucleolytic ribozymes, and the only one for which there is no crystal structure. It can be divided into a trans -acting ribozyme, consisting of five helices organized by two three-way helical junctions, and a stem-loop substrate with which it interacts, primarily by tertiary interactions. We have determined the global fold of the ribozyme, and the manner by which it interacts with the substrate. The substrate interacts with a cleft formed between helices II and VI (organized by the lower helical junction), where it contacts the A730 loop, the probable active site of the ribozyme. Within this loop, there is a critical adenine base (A756) that is a candidate for direct nucleobase participation in the cleavage reaction.
瓦库德卫星核酶是小型核酸裂解核酶中最大的一种，也是唯一没有晶体结构的核酶。它可分为一个反式作用核酶，由两个三向螺旋连接组织的五个螺旋组成，以及一个茎环底物，它主要通过三级相互作用与之相互作用。我们已经确定了核酶的整体折叠结构及其与底物相互作用的方式。底物与螺旋II和VI（由较低的螺旋连接组织）之间形成的裂隙相互作用，在那里它接触到A730环，这可能是核酶的活性位点。在这个环内，有一个关键的腺嘌呤碱基（A756），它可能直接参与碱基在切割反应中的作用。
