基于光谱法研究盐酸胍诱导的人血红蛋白去折叠过程

借助于紫外-可见吸收光谱法、荧光光谱法以及停流-荧光光谱法研究了盐酸胍(GdmHcl)诱导人血红蛋白的去折叠过程。实验发现，盐酸胍诱导的血红蛋白去折叠有两个不同的过程，即随着GdmHcl浓度增加到1.0 mol·L-1左右时，血红蛋白亚基发生解聚，形成中间态;持续增加其浓度时，各亚基发生内部去折叠，最终导致血红素发生崩解。加入还原剂(β-巯基乙醇)对血红蛋白亚基解聚、血红素崩解有协同作用且直接引起亚基和全分子同步变构。血红蛋白去折叠过程从“三态模型”转变为“二态模型”。

Spectroscopic Studies of Guanidine Hydrochloride-Induced Unfolding of Hemoglobin

In the present paper, based on the ultraviolet-visible (UV-Vis) absorption spectroscopy, fluorescence spectroscopy, and stopped flow-fluorescence spectroscopy, the authors studied the protein unfolding process of hemoglobin induced by GdmHcl. The experiments result shows that there were two different procedures about GdmHcl inducing hemoglobin unfolding from the evidences of UV-Vis absorption spectrum and fluorescence phase diagrams. Namely, the hemoglobin subunit exhibits depolymerization, forming the intermediates when incubated with GdmHcl at the concentration of 1.0 mol·L-1. With the increase in the concentration, various subunit structure became loose gradually, and the protoheme collapsed eventually. UV-Vis absorption spectroscopy indicates that the addition of reductant can cooperate with the depolymerization of hemoglobin subunit and the disaggregation of protoheme. The reductant results in the unfolding procedure that hemoglobin from “three-state model” turns into “two-state model”.