Mirchev R, Ferrone F A
Department of Physics and Atmospheric Science, Drexel University, Philadelphia, PA 19104, USA.
J Mol Biol. 1997 Feb 7;265(5):475-9. doi: 10.1006/jmbi.1996.0759.
Sickle hemoglobin molecules assemble into polymers composed of seven helically twisted double strands. Intermolecular contacts involving the mutation sites within the double strands are well established. We show that the same contact sites are present at the polymer surface on four of the ten exterior molecules in each layer, and demonstrate that the identical contact geometry can be achieved between polymers as found within the double strands. This provides a structural rationale for the exponential rate of polymer growth that characterizes the kinetics of gelation. This also gives a structural basis for the cross-linking which solidifies the polymer gel. In the absence of these surface contact regions sickle cell disease would be a much milder syndrome.
镰状血红蛋白分子组装成由七条螺旋扭曲双链组成的聚合物。涉及双链内突变位点的分子间接触已得到充分证实。我们发现，在每层十个外部分子中的四个分子上，聚合物表面存在相同的接触位点，并证明聚合物之间可以实现与双链内相同的接触几何结构。这为表征凝胶化动力学的聚合物指数增长速率提供了结构依据。这也为固化聚合物凝胶的交联提供了结构基础。如果没有这些表面接触区域，镰状细胞病将会是一种温和得多的综合征。
