van Mierlo C P, Darby N J, Neuhaus D, Creighton T E
MRC Laboratory of Molecular Biology, Cambridge, England.
J Mol Biol. 1991 Nov 20;222(2):353-71. doi: 10.1016/0022-2836(91)90216-s.
An analogue of the BPTI folding intermediate that contains only the disulphide bonds between Cys14 and Cys38 and between Cys30 and Cys51 has been prepared in Escherichia coli by protein engineering methods. The other two Cys residues of native BPTI (at positions 5 and 55) have been replaced by Ser. Essentially complete proton resonance assignments of the analogue were obtained by employing two-dimensional 1H nuclear magnetic resonance techniques. The intermediate has a more extended conformation in the N-terminal (residues 1 to 7) region and there are other differences in the C-terminal (residues 55 to 58) region. The remainder of the protein is substantially identical to native BPTI. The conformational properties of the analogue can explain several aspects of the kinetic role that the normal (14-38, 30-51) intermediate plays in the folding of BPTI.
通过蛋白质工程方法在大肠杆菌中制备了一种BPTI折叠中间体类似物，该类似物仅包含半胱氨酸14与半胱氨酸38之间以及半胱氨酸30与半胱氨酸51之间的二硫键。天然BPTI的其他两个半胱氨酸残基（第5位和第55位）已被丝氨酸取代。通过二维¹H核磁共振技术获得了该类似物基本完整的质子共振归属。该中间体在N端（第1至7位残基）区域具有更伸展的构象，并且在C端（第55至58位残基）区域存在其他差异。蛋白质的其余部分与天然BPTI基本相同。该类似物的构象特性可以解释正常（14 - 38，30 - 51）中间体在BPTI折叠过程中动力学作用的几个方面。
