Seckfort Danielle, Montgomery Pettitt B
Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, Texas.
Department of Biochemistry and Molecular Biology, Sealy Center for Structural Biology, University of Texas Medical Branch, Galveston, Texas.
Biopolymers. 2019 Jan;110(1):e23239. doi: 10.1002/bip.23239. Epub 2018 Nov 28.
The Lac system of genes has been pivotal in understanding gene regulation. When the lac repressor protein binds to the correct DNA sequence, the hinge region of the protein goes through a disorder to order transition. The structure of this region of the protein is well understood when it is in this bound conformation, but less so when it is not. Structural studies show that this region is flexible. Our simulations show this region is extremely flexible in solution; however, a high concentration of salt can help kinetically trap the hinge helix. Thermodynamically, disorder is more favorable without the DNA present.
基因的乳糖操纵子系统在理解基因调控方面一直起着关键作用。当乳糖阻遏蛋白与正确的DNA序列结合时，该蛋白的铰链区会经历从无序到有序的转变。当该蛋白的这一区域处于这种结合构象时，其结构已得到充分了解，但在未结合时则了解较少。结构研究表明该区域是灵活可变的。我们的模拟显示，在溶液中该区域极其灵活；然而，高浓度的盐有助于在动力学上捕获铰链螺旋。从热力学角度来看，没有DNA存在时无序状态更有利。
