Travaglini Allocatelli C, Cutruzzolà F, Brancaccio A, Vallone B, Brunori M
Department of Biochemical Sciences A Rossi Fanelli, University of Rome La Sapienza, Italy.
FEBS Lett. 1994 Sep 19;352(1):63-6. doi: 10.1016/0014-5793(94)00918-x.
The contribution to oxygen stabilization of a tyrosine residue in topological position (B10) has been studied in sperm whale myoglobin by simultaneous replacement of residues at positions (B10), (E7) and (E10) as suggested by analysis of the sequence of high oxygen affinity hemoglobins, such as that of the nematode Ascaris suum. Kinetic and equilibrium experiments with the gaseous ligands oxygen and carbon monoxide show that indeed the introduction of tyrosine (B10), together with replacement of the distal histidine (E7) with glutamine, is associated with a large decrease in the oxygen dissociation rate constant. Our results are consistent with the possible formation in the distal pocket of two hydrogen bonds with the iron-bound oxygen.
通过同时替换（B10）、（E7）和（E10）位的残基，如对线虫猪蛔虫高氧亲和力血红蛋白序列分析所建议的那样，研究了抹香鲸肌红蛋白中拓扑位置（B10）的酪氨酸残基对氧稳定性的贡献。使用气态配体氧气和一氧化碳进行的动力学和平衡实验表明，确实，酪氨酸（B10）的引入，以及用谷氨酰胺替换远端组氨酸（E7），与氧解离速率常数的大幅降低有关。我们的结果与远端口袋中可能与铁结合的氧形成两个氢键一致。
