ABSTRACT

Water soluble calixarenes are versatile mediators of protein assembly, including the fabrication of crystalline frameworks. Here, we report the X-ray crystal structure of cytochrome c (cytc) co-crystallised with two different calixarenes: phosphonato-calix[6]arene (pclx₆) and sulfonato-calix[8]arene (sclx₈). Each calixarene type acts as an independent molecular glue that mediates cytc dimers within the crystal. The calixarene-mediated dimers combine to yield chains of cytc-sclx₈-cytc-pclx₆-pclx₆ repeating units. These supramolecular copolymer units pack together, via a protein-protein interface, to yield a porous dendrite-like assembly. Interestingly, the tri-component framework has features in common with previously reported structures of cytc in complex with pclx₆ or sclx₈. Known protein-calixarene ‘building blocks’ combine in novel ways to yield the tri-component assembly, highlighting the versatility of calixarene molecular glues in protein crystal engineering.

摘要

水溶性杯芳烃是蛋白质组装的多功能介质，包括晶体框架的制造。在这里，我们报告了与两种不同杯芳烃共结晶的细胞色素c (cyt c )的 X 射线晶体结构：膦酸-杯[6]芳烃 ( pclx ₆ ) 和磺基-杯[8] 芳烃 ( sclx ₈ )。每种杯芳烃都充当独立的分子胶，介导晶体内的细胞色素c二聚体。杯芳烃-介导的二聚体结合以产链的细胞色素C ^ - SCLx为₈ -cyt Ç - pclx ₆ -pclx ₆重复单位。这些超分子共聚物单元通过蛋白质-蛋白质界面堆积在一起，形成多孔的树突状组装体。有趣的是，三组分框架具有与先前报道的与pclx ₆或sclx ₈复合的 cyt c结构的共同特征。已知的蛋白质-杯芳烃“积木”以新颖的方式结合产生三组分组装，突出了杯芳烃分子胶在蛋白质晶体工程中的多功能性。