脱辅基神经红蛋白热稳定性的光谱法研究

Spectroscopic studies on the thermostability of apo-Neuroglobin

采用酸丙酮法制备了脱辅基神经红蛋白(apo-Ngb)。利用紫外-可见吸收光谱和圆二色光谱(CD)对apo-Ngb的热稳定性进行了研究。结果表明,在高温下apo-Ngb发生了变性,其二级结构遭到破坏,α-螺旋的含量减少。计算得到了apo-Ngb热变性的中点温度(61.8℃)和热力学参数(ΔH=93.1 kJ·mol-1,ΔS=277.8J·mol-1·K-1)。与Ngb相比,由于血红素辅基的去除,apo-Ngb蛋白肽链结构变得疏松无序,从而使apo-Ngb的热稳定性有所降低。

Apo-Neuroglobin（apo-Ngb） was prepared from Ngb by acid-acetone method.Thermostability of apo-Ngb was investigated by UV-Vis absorption spectra and circular dichroism（CD） spectra.The results showed that apo-Ngb become denatured at high temperature and its secondary structure was destroyed,leading to decrease of its α-helical content.The calculated midpoint temperature for thermal denaturation of apo-Ngb was 61.8℃ and thermodynamic parameters for thermal denaturation of apo-Ngb were ΔH = 93.1 kJ.mol-1 and ΔS = 277.8 J.mol 1.K-1,respectively.Compared with Ngb,apo-Ngb became conformational disorder because of the removing of heme group from Ngb,so that its thermostability was reduced.