MODEL FOR A DNA-MEDIATED SYNAPTIC COMPLEX SUGGESTED BY CRYSTAL PACKING OF GAMMA-DELTA RESOLVASE SUBUNITS
MODEL FOR A DNA-MEDIATED SYNAPTIC COMPLEX SUGGESTED BY CRYSTAL PACKING OF GAMMA-DELTA RESOLVASE SUBUNITS
复制标题
DOI：
10.1002/j.1460-2075.1994.tb06413.x
复制
发表时间：
1994-04-01
期刊：
影响因子：
11.4
通讯作者：
STEITZ, TA
中科院分区：
文献类型：
--
作者：
RICE, PA;STEITZ, TA
完整的γ-δ解离酶的12个亚基在六边形晶体形式的单位细胞中的包装排列表明了涉及DNA介导的突触中间体的位点特异性重组的模型。晶体结构已通过分子置换确定，并在2.8/3.5埃分辨率下部分细化。虽然小的DNA结合域在这些晶体中是无序的，但包装考虑表明，晶体中只有一小部分空间可以容纳其大小的域。一个家庭的相关模型之间的突触复合物的tno DNA双链体和12个单体的安排，位于晶体是一致的，与已知的拓扑结构的复合物和之间的距离resolvase二聚体结合位点pr DNA;此外，这些模型将两个DNA重组位点置于两个解离酶二聚体之间彼此接触，这意味着链交换是通过直接DNA-DNA相互作用完成的。一个主要的角色假设，然后，为resolvase蛋白组装是稳定的res DNA结构，是接近的拓扑过渡状态的反应。
The packing arrangement of the 12 subunits of intact gamma delta resolvase in the unit cell of a hexagonal crystal form suggests a model for site-specific recombination that involves a DNA-mediated synaptic intermediate. The crystal structure has been determined by molecular replacement and partially refined at 2.8/3.5 Angstrom resolution. Although the small DNA-binding domain is disordered in these crystals, packing considerations show that only a small region of space in the crystal could accommodate a domain of its size. A family of related models for a synaptic complex between tno DNA duplexes and 12 monomers that are arranged as situated in the crystal is consistent with the known topology of the complex and the distances between the three resolvase dimer-binding sites pr DNA; further, these models place the two DNA recombination sites in contact with each other between two resolvase dimers, implying that strand exchange is accomplished through direct DNA-DNA interaction. A major role postulated, then, for the resolvase protein assembly is to stabilize a res DNA structure that is close to the topological transition state of the reaction.