Lovell Scott, Goryshin Igor Y, Reznikoff William R, Rayment Ivan
Department of Biochemistry, University of Wisconsin, Madison, Wisconsin 53706, USA.
Nat Struct Biol. 2002 Apr;9(4):278-81. doi: 10.1038/nsb778.
A synaptic complex of Tn5 transposase with an extended outside end DNA duplex was prepared and crystallized, and its crystal structure was determined in an effort to reveal the role of metal ions in catalysis. Two Mn2+ ions bound to the active site when a single nucleotide of donor DNA was added to the 3' end of the transferred strand. Marked conformational changes were observed in the DNA bases closest to the active site. The position of the metal ions and the conformational changes of the DNA provide insight into the mechanism of hairpin formation and cleavage, and is consistent with a two-metal model for catalysis.
制备并结晶了转座酶Tn5与延伸的外侧末端DNA双链体的突触复合体，并测定了其晶体结构，以揭示金属离子在催化中的作用。当在转移链的3'末端添加一个供体DNA单核苷酸时，两个Mn2+离子结合到活性位点。在最接近活性位点的DNA碱基中观察到明显的构象变化。金属离子的位置和DNA的构象变化为发夹形成和切割机制提供了见解，并且与催化的双金属模型一致。
