盐酸胍诱导的apo-CP43去折叠过程

膜蛋白生物合成与色素组装中蛋白的稳定性可以通过去折叠条件与过程分析得到.利用色氨酸荧光光谱和ANS荧光光谱研究了apo-CP43在盐酸胍条件下的稳定性.色氨酸荧光光谱观测到apo-CP43在盐酸胍作用下去折叠进程的主要特征:荧光强度先是逐渐降低,之后再逐渐升高,而最大荧光发射峰位置则一直持续红移.盐酸胍处理后apo-CP43的F360 nm/F335 nm比值逐渐增大,表明荧光最大发射峰逐步红移.当盐酸胍浓度约为5.5 mol/L时,去折叠比例趋于相对稳定状态,说明此时apo-CP43已经基本完成去折叠.荧光相图法结果显示盐酸胍诱导apo-CP43变性的过程符合三态模型.ANS荧光测定数据显示盐酸胍处理之后最大ANS荧光发射峰位置红移,并且荧光强度逐渐降低.以上数据表明在盐酸胍条件下apo-CP43是一个相对比较稳定的蛋白.

Unfolding of apo-CP43 Induced by Guanidine Hydrochloride

The stability of apo-CP43 induced by guanidine hydrochloride was studied by using tryptophan fluorescence spectroscopy and extrinsic ANS fluorescence spectroscopy.The main characteristics of the unfolding process in the case of guanidine hydrochloride monitored by tryptophan fluorescence were that the fluorescence intensity initially gradually decreased,and then increased,however,the maximum emission wavelength continually red-shifted.The F360 nm/F335 nm was increased gradually under the guanidine hydrochloride,indicated that the maximum emission wavelength red-shifted.The fraction unfolding was in relatively stable state when the guanidine hydrochloride concentration in denaturation solution was about 5.5 mol/L,suggested that the unfolding of the apo-CP43 completed.The result of the phase diagrams indicated that the denaturation process of apo-CP43 induced by guanidine hydrochloride was consistent with typical three-state model.It was also revealed that ANS fluorescence decreased after guanidine hydrochloride treatment.This study suggested that apo-CP43 was a relative stability protein under guanidine hydrochloride.