Nadolny C, Kempf I, Zundel G
Institut für Physikalische Chemie der Universität München, Germany.
Biol Chem Hoppe Seyler. 1993 Jun;374(6):403-7. doi: 10.1515/bchm3.1993.374.1-6.403.
The specific interactions of 2,3-bisphosphoglycerate (BPG) with human deoxy-hemoglobin (deoxy-HbA) are studied by difference FTIR spectroscopy. Due to these interaction effects the O2 affinity of the hemoglobins is regulated. In deoxy-HbA a NH+ ... -OOC hydrogen bond is formed between beta 82 Lys and the carboxylate group of BPG. The phosphate groups of BPG are completely deprotonated causing a strong electrostatic stress within the Hb molecule. The aminotermini (beta 1 Val) interact with the phosphate groups but no hydrogen bonds are formed. The interaction is limited to an electrostatic interaction between the NH3+ and the negatively charged phosphate group, i.e. only ionic bonds are built up. The histidines beta 2 and beta 143 of the two beta-chains form hydrogen bonds with the phosphates. To each phosphate two bonds are formed. These bonds polarize each other and hence only the polar structures NH+ ... -OP of the hydrogen bonds are realized. This follows since no protons are present at the BPG molecules. Thus, caused by the hydrogen bonds and the electrostatic interaction the conformation of HbA is changed by BPG in the way that the T-structure is favored and hence the affinity for oxygen is decreased.
采用差示傅里叶变换红外光谱法研究了2,3-二磷酸甘油酸（BPG）与人脱氧血红蛋白（deoxy-HbA）的特异性相互作用。由于这些相互作用效应，血红蛋白的O2亲和力得到调节。在脱氧-HbA中，β82赖氨酸的NH+与BPG的羧基之间形成了氢键。BPG的磷酸基团完全去质子化，在Hb分子内产生强烈的静电应力。氨基末端（β1缬氨酸）与磷酸基团相互作用，但未形成氢键。这种相互作用仅限于NH3+与带负电荷的磷酸基团之间的静电相互作用，即仅形成离子键。两条β链的组氨酸β2和β143与磷酸形成氢键。每个磷酸形成两个键。这些键相互极化，因此仅实现了氢键的极性结构NH+...-OP。这是因为BPG分子上不存在质子。因此，由于氢键和静电相互作用，BPG改变了HbA的构象，使得T结构更受青睐，从而降低了对氧气的亲和力。
