The architectures of tandem-repeat proteins are distinct from those of globular proteins. Individual modules, each comprising small structural motifs of 20–40 residues, are arrayed in a quasi one-dimensional fashion to form striking, elongated, horseshoe-like, and superhelical architectures, stabilized solely by short–range interaction. The spring-like shapes of repeat arrays point to elastic modes of action, and these proteins function as adapter molecules or ‘hubs,’ propagating signals within multi-subunit assemblies in diverse biological contexts. This flexibility is apparent in the dramatic variability observed in the structures of tandem-repeat proteins in different complexes. Here, using computational analysis, we demonstrate the striking ability of just one or a few global motions to recapitulate these structures. These findings show how the mechanics of repeat arrays are robustly enabled by their unique architecture. Thus, the repeating architecture has been optimized by evolution to favor functional modes of motions. The global motions enabling functional transitions can be fully visualized at http://bahargroup.org/tr_web.

串联重复蛋白的结构与球状蛋白的结构不同。每个单独的模块都包含 20-40 个残基的小结构基序，以准一维方式排列，形成引人注目的、细长的、马蹄形和超螺旋结构，仅通过短程相互作用来稳定。重复阵列的弹簧状形状表明了弹性作用模式，这些蛋白质充当接头分子或“枢纽”，在不同的生物环境中的多亚基组装体中传播信号。这种灵活性在不同复合物中串联重复蛋白的结构中观察到的巨大变异性中是显而易见的。在这里，通过计算分析，我们展示了仅一个或几个全局运动来概括这些结构的惊人能力。这些发现表明重复阵列的机制如何通过其独特的架构得到有力支持。因此，重复架构已通过进化进行了优化，以支持功能性运动模式。实现功能转换的全局运动可以在http://bahargroup.org/tr_web上完全可视化。