Morimatsu K, Horii T
Department of Molecular Protozoology, Osaka University, Japan.
Eur J Biochem. 1995 Dec 15;234(3):695-705. doi: 10.1111/j.1432-1033.1995.695_a.x.
The first DNA-binding site (site I) of RecA protein on the filament has been mapped. RecA protein was covalently cross-linked with a 55-base synthetic single-stranded DNA which was a good substrate for the RecA-mediated strand exchange reaction. The cross-linking sites of protein were determined in the regions spanning RecA residues 64-68, 89-106, 178-183, 199-216 and 257-280. The cross-linking in the residues 64-68, 89-106, 199-216 and 257-280 would be due to the cross-linking of Tyr65, Tyr103, disordered loop 2, and Tyr264, respectively. These regions form a DNA-binding surface centered around the beta-sheet spanning residues 243-257. In the P6(1) crystal filament, the DNA-binding surface is near the RecA-RecA interface but are not in the filament axis. The data implicate a mechanism whereby the DNA binding surface would be led into the filament axis by a conformational change from inactive filament as the P6(1) structure to active filament as the RecA-DNA-ATP complex.
RecA蛋白细丝上的第一个DNA结合位点（位点I）已被定位。RecA蛋白与一段55个碱基的合成单链DNA共价交联，该单链DNA是RecA介导的链交换反应的良好底物。蛋白质的交联位点在跨越RecA残基64 - 68、89 - 106、178 - 183、199 - 216和257 - 280的区域中确定。残基64 - 68、89 - 106、199 - 216和257 - 280中的交联分别是由于Tyr65、Tyr103、无序环2和Tyr264的交联。这些区域形成了一个以跨越残基243 - 257的β折叠为中心的DNA结合表面。在P6(1)晶体细丝中，DNA结合表面靠近RecA - RecA界面，但不在细丝轴上。这些数据暗示了一种机制，即随着从P6(1)结构的无活性细丝到RecA - DNA - ATP复合物的活性细丝的构象变化，DNA结合表面将通过这种变化被引入细丝轴。
