Molten Globule State of Proteins-Conformation, Stability, and Its Physiological Role

熔融小球状态是一种致密的变性状态，具有显著的二级结构，但在很大程度上是无序的三级结构，被认为是蛋白质折叠的主要中间状态，并被认为参与了体内的各种过程。然而，仍有许多未知之处--特别是构象稳定的机制及其生理作用。为了澄清这些问题，我们开展了国际科学研究计划，取得了以下结果：1)熔融球状态的构象和稳定性用溶液X射线散射法研究了脱蛋白肌红蛋白各种构象状态的结构特征。结果表明，熔融球状态是从本征状态扩展而来的，它包含一个由螺旋团和张开的尾巴组成的核心。用卡路里…研究了疏水和静电相互作用在稳定无肌球蛋白和细胞色素c熔球状态中的作用。更多的测光和圆二色性。结果表明，电荷排斥力和疏水作用力的平衡决定了熔融球态的稳定性。通过比较各种构象状态，我们构建了折叠轮廓，表明随着二级结构的形成，蛋白质变得更加致密。分子伴侣识别底物蛋白的性质研究了GroEL与底物蛋白相互作用的机理。我们发现GroEL识别底物蛋白的柔性和暴露的疏水簇。另一方面，Dank识别出更多的无序构象状态。3.熔融球态的分析电喷雾质谱仪分析熔融球态的H/D交换反应。结果表明，质谱仪可用于表征熔融球状态的结构柔性。较少

The molten globule, state, a compact denatured state with significant secondary structure but a largely disordered tertiary structure, has been proposed to be a major intermediate state in protein folding and its participation in various in vivo processes has been suggested. However, much remains unknown-particularly the mechanism of conformational stability and its physiological role. We carried out the International Scientific Research Program in order to clarify these problems and obtained the following results.1)Conformation and stability of the molten globule state Structural characteristics of various conformational state of apomyoglobin were studied by solution X-ray scattering. The results show that the molten globule state is expanded from the native state and that it contains a core comprising a cluster of helices and flaring tails. Role of hydrophobic and electrostatic interactions in stabilizing the molten globule state of apomyogobin and cytochrome c was studied by calorim … More etry and circular dichroism. It was shown that the stability of the molten globule state is critically determined by a balance of charge repulsive forces and hydrophobic forces. By comparing the various conformational states, we constructed a folding profile, which shows that the protein becomes more compact with formation of the secondary structure. The profiles are consistent with the prediction on the basis of the statistical mechanical theory.2.Nature of substrate proteins recognized by molecular chaperons Mechanism of interaction of GroEL and substrate proteins was studied. We found that GroEL recognizes the flexible and exposed hydrophobic clusters of the substrate proteins. On the other hand, DanK was found to recognize more disordered conformational states.3.Analysis of the molten globule state by mass spectrometryH/D exchange reaction of the molten globule state was analyzed by electrospray mass spectrometry. It was indicated that mass spectrometry is useful to characterize the structural flexibility of the molten globule state. Less