摘要
运用时间分辨红外光谱对碱金属盐溶液诱导发生的蜘蛛丝蛋白膜的构象转变过程进行跟踪研究.结果表明虽然构象转变速率为NaCl>KCl>LiCl,但是在最终完成构象转变的丝蛋白膜中 β 折叠结构的比例却是KCl>LiCl>NaCl.综合膜的构象转变速率和程度,可以认为在三种碱金属盐中,KCl最有利于丝蛋白的构象转变,这与钾在蜘蛛吐丝过程中起重要作用的观点(即发现在丝腺体中的丝蛋白胶状物,越靠近吐丝口,钾离子含量越高)相吻合.同时根据对构象转变动力学数据的分析,认为蜘蛛丝蛋白膜的构象转变由快慢两相组成,其中较快相(相应时间常数为5min左右)对应于链段运动引起的构象转变,而较慢相(相应时间常数为 5 0min左右)
The conformation transition processes of Nephila spidroin membranes induced by alkali salt solutions were monitored by time-resolved FTIR spectroscopy. Though the transition rate of spidroin in the membrane was NaCl > KCI > LiCI, the beta-sheet structure content in the membrane ( after the conformation transition completed) was KCl > LiCl > NaCl. Comparing the transition rate and final beta-sheet structure content in the membrane, KCI has the best effect in-inducing the conformation transition of spidroin membrane among the dime alkali salts we used. This supports the assumption that the K+ ions play an important role in the spinning process of spiders. In the meantime, the conformation transition process was indicated to have two intermediate states that contain different levels of beta-sheet structure. The first phase (fast phase, with a time constant of similar to 5 min) was assigned to the beta-sheet formation by segments movement, while the second phase (slow phase, with a time constant of similar to 50 min) was attributed to the whole macromolecular rearrangement.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
2002年第12期2203-2208,共6页
Acta Chimica Sinica
基金
教育部高等学校骨干教师
中英科技合作基金
国家自然科学基金(No.2 99740 0 5)
英国BiotechnologyandBiologicalSciencesResearchCouncil(BBSRC)基金
EngineeringandPhysicalSciencesResearchCouncil(EPSRC)基金资助项目
