Monera O D, Zhou N E, Lavigne P, Kay C M, Hodges R S
Department of Biochemistry and the Protein Engineering Network of Centers of Excellence, University of Alberta, Edmonton, Alberta, Canada T6G 2H7.
J Biol Chem. 1996 Feb 23;271(8):3995-4001. doi: 10.1074/jbc.271.8.3995.
The orientation of alpha-helical chains in two-stranded coiled-coils has been shown to be determined by the presence of favorable interchain electrostatic interactions. In this study, we used de novo designed 35-residue peptides to show that when interchain electrostatic interactions are not a factor in coiled-coil formation, the relative positions of Ala residues in the middle heptad can control the parallel or antiparallel orientation of alpha-helical chains in coiled-coils. The peptides formed four-stranded coiled-coils where the helices are either all-parallel or all-antiparallel with respect to their nearest neighbor. The common structural element in these four-stranded coiled-coils is an alternating pair of Ala and Leu residues (Ala-Leu-Ala-Leu) in each of the two planes in the middle heptad. These results indicate that both the relative positions of the Ala residues in the hydrophobic core and the interchain electrostatic interactions between charged residues in the e and g positions should be considered in designing coiled-coils with the desired number of strands in the multiple-stranded assembly. These design elements are also important in orienting functional groups or domains attached to the terminals ends of a coiled-coil carrier.
在双链卷曲螺旋中，α-螺旋链的方向已被证明是由有利的链间静电相互作用决定的。在本研究中，我们使用从头设计的35个残基的肽来表明，当链间静电相互作用不是卷曲螺旋形成的一个因素时，中间七肽中Ala残基的相对位置可以控制卷曲螺旋中α-螺旋链的平行或反平行方向。这些肽形成了四链卷曲螺旋，其中螺旋相对于其最近邻要么全是平行的，要么全是反平行的。在这些四链卷曲螺旋中，共同的结构元件是中间七肽的两个平面中每个平面上交替出现的一对Ala和Leu残基（Ala-Leu-Ala-Leu）。这些结果表明，在设计多链组装中具有所需链数的卷曲螺旋时，应同时考虑疏水核心中Ala残基的相对位置以及e和g位置带电残基之间的链间静电相互作用。这些设计元件对于定向连接到卷曲螺旋载体末端的官能团或结构域也很重要。
