Ferreiro Diego U, Sánchez Ignacio E, de Prat Gay Gonzalo
Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas de Buenos Aires-Consejo Nacional de Investigaciones Científicas y Técnicas de Argentina, Patricias Argentinas 435, 1405 Buenos Aires, Argentina.
Proc Natl Acad Sci U S A. 2008 Aug 5;105(31):10797-802. doi: 10.1073/pnas.0802383105. Epub 2008 Jul 29.
We describe the formation of protein-DNA contacts in the two-state route for DNA sequence recognition by a transcriptional regulator. Surprisingly, direct sequence readout establishes in the transition state and constitutes the bottleneck of complex formation. Although a few nonspecific ionic interactions are formed at this early stage, they mainly play a stabilizing role in the final consolidated complex. The interface is fairly plastic in the transition state, likely because of a high level of hydration. The overall picture of this two-state route largely agrees with a smooth energy landscape for binding that speeds up DNA recognition. This "direct" two-state route differs from the parallel multistep pathway described for this system, which involves nonspecific contacts and at least two intermediate species that must involve substantial conformational rearrangement in either or both macromolecules.
我们描述了转录调节因子识别DNA序列的两态途径中蛋白质-DNA接触的形成。令人惊讶的是,直接序列读出在过渡态建立,并构成复合物形成的瓶颈。尽管在这个早期阶段会形成一些非特异性离子相互作用,但它们主要在最终形成的稳定复合物中起稳定作用。过渡态下的界面相当可塑性,可能是由于高度水合作用。这种两态途径的整体情况在很大程度上与加速DNA识别的平滑结合能量景观一致。这种“直接”的两态途径不同于该系统所描述的平行多步途径,后者涉及非特异性接触以及至少两个中间物种,这两个中间物种必然涉及一个或两个大分子中的大量构象重排。