Nicola N A, Leach S J
Eur J Biochem. 1977 Aug 15;78(1):133-40. doi: 10.1111/j.1432-1033.1977.tb11722.x.
Structural rearrangements in sperm whale myoglobin and leghaemoglobins caused by changes in the spin or oxidation state of the iron as a consequence of ligand binding have been measured by difference spectroscopy in the ultraviolet. When compared with the high-spin acetate complex, ligands which cause a transition to the low-spin state also cause large perturbations of tyrosine(s) remote from the haem pocket in myoglobin but only minor perturbations of tryptophan (s) in leghaem calobin. This may indicate a weaker coupling between events at the haem site and conformational changes in the protein in leghaemoglobins. The absorption spectra of various haem-liganded forms of the two proteins as well as the binding of the dye rose Bengal to the two apoproteins are consistent with weaker interactions between the haem ano apoprotein and a more solvent-exposed haem pocket in leghaemoglobin compared with myoglobin.
通过紫外差示光谱法测定了由于配体结合导致铁的自旋或氧化态变化而引起的抹香鲸肌红蛋白和豆血红蛋白的结构重排。与高自旋醋酸盐配合物相比，导致向低自旋态转变的配体也会引起肌红蛋白中远离血红素口袋的酪氨酸发生较大扰动，但在豆血红蛋白中仅引起色氨酸的轻微扰动。这可能表明豆血红蛋白中血红素位点的事件与蛋白质构象变化之间的耦合较弱。两种蛋白质的各种血红素配体形式的吸收光谱以及染料孟加拉玫瑰红与两种脱辅基蛋白的结合情况表明，与肌红蛋白相比，豆血红蛋白中血红素与脱辅基蛋白之间的相互作用较弱，血红素口袋更易暴露于溶剂中。
