Arrangement of RecA protein in its active filament determined by polarized-light spectroscopy
Arrangement of RecA protein in its active filament determined by polarized-light spectroscopy
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DOI：
10.1073/pnas.142404499
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发表时间：
2002-09-03
影响因子：
11.1
通讯作者：
Nordén, B
中科院分区：
文献类型：
--
作者：
Morimatsu, K;Takahashi, M;Nordén, B
利用线性二色（LD）偏振光光谱测定了RecA在其与DNA的大丝状复合体中的排列，该复合体具有同源重组活性。两种色氨酸和7种酪氨酸残基的角取向数据，从野生型RecA与突变型RecA的差异LD中推断出来，这些突变型被设计为衰减选定残基的紫外线吸收，显示了相对于没有DNA的RecA亚基在晶体中的排列，大约旋转了40度。此外，研究人员还观察到参与DNA结合和RecA-RecA接触的酪氨酸残基的构象变化，从而可能与丝的整体结构及其生物学功能有关。所提出的光谱方法，称为“位点特异性线性二色性”（SSLD），也可能在其他不适合x射线晶体学或核磁共振结构分析的生物重要纤维复合物中找到强有力的应用。
Linear dichroism (LD) polarized-light spectroscopy is used to determine the arrangement of RecA in its large filamentous complex with DNA, active in homologous recombination. Angular orientation data for two tryptophan and seven tyrosine residues, deduced from differential LD of wild-type RecA vs. mutants that were engineered to attenuate the UV absorption of selected residues, revealed a rotation by some 40degrees of the RecA subunits relative to the arrangement in crystal without DNA. In addition, conformational changes are observed for tyrosine residues assigned to be involved in DNA binding and in RecA-RecA contacts, thus potentially related to the global structure of the filament and its biological function. The presented spectroscopic approach, called "Site-Specific Linear Dichroism" (SSLD), may find forceful applications also to other biologically important fibrous complexes not amenable to x-ray crystallographic or NMR structural analysis.