McGregor Natalie, Ayora Sylvia, Sedelnikova Svetlana, Carrasco Begona, Alonso Juan C, Thaw Paul, Rafferty John
The Krebs Institute, Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom.
Structure. 2005 Sep;13(9):1341-51. doi: 10.1016/j.str.2005.05.011.
We have determined the structure of the enzyme RecU from Bacillus subtilis, that is the general Holliday junction resolving enzyme in Gram-positive bacteria. The enzyme fold reveals a striking similarity to a class of resolvase enzymes found in archaeal sources and members of the type II restriction endonuclease family to which they are related. The structure confirms the presence of active sites formed around clusters of acidic residues that we have also shown to bind divalent cations. Mutagenesis data presented here support the key role of certain residues. The RecU structure suggests a basis for Holliday junction selectivity and suggests how sequence-specific cleavage might be achieved. Models for a resolvase-DNA complex address how the enzyme might organize junctions into an approximately 4-fold symmetric form.
我们已经确定了来自枯草芽孢杆菌的RecU酶的结构，该酶是革兰氏阳性细菌中的通用霍利迪连接体解离酶。这种酶的折叠结构与在古菌来源中发现的一类解离酶以及与之相关的II型限制性内切酶家族成员有着惊人的相似性。该结构证实了在酸性残基簇周围形成的活性位点的存在，我们还表明这些位点能结合二价阳离子。此处给出的诱变数据支持了某些残基的关键作用。RecU结构为霍利迪连接体的选择性提供了基础，并提示了如何实现序列特异性切割。解离酶 - DNA复合物的模型阐述了该酶如何将连接体组织成近似四倍对称的形式。
