Bryson J W, Desjarlais J R, Handel T M, DeGrado W F
The DuPont Merck Pharmaceutical Company, Wilmington, Delaware, USA.
Protein Sci. 1998 Jun;7(6):1404-14. doi: 10.1002/pro.5560070617.
A monomolecular native-like three-helix bundle has been designed in an iterative process, beginning with a peptide that noncooperatively assembled into an antiparallel three-helix bundle. Three versions of the protein were designed in which specific interactions were incrementally added. The hydrodynamic and spectroscopic properties of the proteins were examined by size exclusion chromatography, sedimentation equilibrium, fluorescence spectroscopy, and NMR. The thermodynamics of folding were evaluated by monitoring the thermal and guanidine-induced unfolding transitions using far UV circular dichroism spectroscopy. The attainment of a unique, native-like state was achieved through the introduction of: (1) helix capping interactions; (2) electrostatic interactions between partially exposed charged residues; (3) a diverse collection of apolar side chains within the hydrophobic core.
通过迭代过程设计了一种单分子天然样三螺旋束，从一种非协同组装成反平行三螺旋束的肽开始。设计了该蛋白质的三个版本，其中特定相互作用被逐步添加。通过尺寸排阻色谱、沉降平衡、荧光光谱和核磁共振研究了蛋白质的流体力学和光谱性质。使用远紫外圆二色光谱监测热诱导和胍诱导的去折叠转变，评估折叠的热力学。通过引入以下因素实现了独特的天然样状态：(1)螺旋封端相互作用；(2)部分暴露的带电残基之间的静电相互作用；(3)疏水核心内多种非极性侧链。
