Electrostatic attraction holds the tetrameric human hemoglobin (α₂β₂) subunits together. The additional negative charge on hemoglobin (Hb) Beckman (βA135D) allows β^V to bind the α globin chain more tightly than normal β. Although local perturbations were evident from H/DX kinetics, the quaternary structure of the hemoglobin tetramer, measured through collision cross‐section, was unaltered.

中文翻译：

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血红蛋白贝克曼变体的四级结构分析及其功能异常的分子解释：基于质谱的方法

静电吸引保持所述四聚体的人血红蛋白（α ₂ β ₂）亚基在一起。上血红蛋白（Hb）贝克曼（βA135D）的额外的负电荷使β ^V到α球蛋白链比正常更β牢固地结合。尽管从H / DX动力学可以明显看出局部扰动，但通过碰撞截面测量的血红蛋白四聚体的四级结构没有改变。