嗜温冷休克蛋白力致去折叠的研究

FORCED UNFOLDING OF MESOPHILIC COLD SHOCK PROTEIN STUDIED BY STEERED MOLECULAR DYNAMICS SIMULATION

嗜温冷休克蛋白拥有一个由五个β股形成的反平行β桶结构,目前已被用于蛋白质去折叠的研究。当使用机械力对嗜温冷休克蛋白进行拉伸研究时,发现嗜温冷休克蛋白的去折叠过程具有明显的中间态。在常速和常力两种情况下对嗜温冷休克蛋白进行拉伸分子动力学模拟,发现其在两种情况下具有相同的去折叠次序,即C端β片层首先去折叠,随后N端β片层去折叠;同时这两种模拟都表现出明确的中间态。研究结果表明,嗜温冷休克蛋白抵抗外力作用除了依赖链间氢键外,分子内的静电相互作用也发挥着重要的作用。

Mesophilic cold shock protein possesses a five-stranded antiparallel 13-barrel, which was investigated experiment of unfolded recently. Molecular dynamics simulation has been used to investigate the force-induced unfolding of mesophilic cold shock protein, finding that the unfolding process occur through intermidate states. Both constant velocity and constant force stretching have been employed to model forced unfolding of Mesophilic Cold Shock Protein, the result that unfolding process of the protein complied with the same sequesce in these two method was obtained, namely unfolding of C-terminal strands at first, subsequently unfolding of N-terminal, and the two methods all showed clear evidence of intermediate states. The results of SMD simulations elucidate that mesophilic cold shock protein is protected against external stress mainly through the interstrand hydrogen bonding, and the ions pair also play an important role in the process of unfolding.