Massey Thomas H, Mercogliano Christopher P, Yates James, Sherratt David J, Löwe Jan
Division of Molecular Genetics, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom.
Mol Cell. 2006 Aug;23(4):457-69. doi: 10.1016/j.molcel.2006.06.019.
FtsK is a DNA translocase that coordinates chromosome segregation and cell division in bacteria. In addition to its role as activator of XerCD site-specific recombination, FtsK can translocate double-stranded DNA (dsDNA) rapidly and directionally and reverse direction. We present crystal structures of the FtsK motor domain monomer, showing that it has a RecA-like core, the FtsK hexamer, and also showing that it is a ring with a large central annulus and a dodecamer consisting of two hexamers, head to head. Electron microscopy (EM) demonstrates the DNA-dependent existence of hexamers in solution and shows that duplex DNA passes through the middle of each ring. Comparison of FtsK monomer structures from two different crystal forms highlights a conformational change that we propose is the structural basis for a rotary inchworm mechanism of DNA translocation.
FtsK是一种DNA转位酶，可协调细菌中的染色体分离和细胞分裂。除了作为XerCD位点特异性重组的激活剂外，FtsK还能快速且定向地转运双链DNA（dsDNA），并能反向转运。我们展示了FtsK马达结构域单体的晶体结构，表明它具有类似RecA的核心结构、FtsK六聚体，还表明它是一个带有大中心环的环以及由两个六聚体头对头组成的十二聚体。电子显微镜（EM）证明了溶液中六聚体的DNA依赖性存在，并表明双链DNA穿过每个环的中间。来自两种不同晶体形式的FtsK单体结构的比较突出了一种构象变化，我们认为这是DNA转位旋转尺蠖机制的结构基础。
