Honzatko R B, Hendrickson W A
Proc Natl Acad Sci U S A. 1986 Nov;83(22):8487-91. doi: 10.1073/pnas.83.22.8487.
The known structures for the tetramers of mammalian and clam hemoglobins provide a point of departure for the modeling of putative dimers of lamprey hemoglobin. The association of subunits is dissimilar for the clam and mammalian tetramers; the superposition of the molecular model for lamprey methemoglobin onto the mammalian and clam tetramers gives five distinct dimers. After energy minimization of the interface regions of the five models, three models afford promising interactions between side chains. One model is analogous to the alpha 1 beta 2 pairing of subunits of mammalian hemoglobins. The other two models are similar to the interfaces between the E and F helices and between the A and B helices of clam hemoglobin. Although the model based on the alpha 1 beta 2 mode of association provides the best explanation of biochemical properties of lamprey hemoglobin, such as the Bohr effect and the dependency of dimer formation on pH, interfaces between the E and F and the A and B helices could be important in the aggregation of monomers of lamprey hemoglobin beyond the level of the dimer.
哺乳动物和蛤蜊血红蛋白四聚体的已知结构为七鳃鳗血红蛋白假定二聚体的建模提供了出发点。蛤蜊和哺乳动物四聚体的亚基缔合情况不同；将七鳃鳗高铁血红蛋白的分子模型叠加到哺乳动物和蛤蜊四聚体上可得到五种不同的二聚体。对这五种模型的界面区域进行能量最小化处理后，其中三种模型在侧链之间产生了有前景的相互作用。一种模型类似于哺乳动物血红蛋白亚基的α1β2配对。另外两种模型类似于蛤蜊血红蛋白E螺旋和F螺旋之间以及A螺旋和B螺旋之间的界面。尽管基于α1β2缔合模式的模型对七鳃鳗血红蛋白的生化特性（如玻尔效应和二聚体形成对pH的依赖性）提供了最佳解释，但E螺旋和F螺旋之间以及A螺旋和B螺旋之间的界面在七鳃鳗血红蛋白单体聚集超过二聚体水平时可能很重要。
