Structurally Diverse Cyclisation Linkers Impose Different Backbone Conformations in Bicyclic Peptides
Structurally Diverse Cyclisation Linkers Impose Different Backbone Conformations in Bicyclic Peptides
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DOI：
10.1002/cbic.201200049
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发表时间：
2012-05-07
期刊：
影响因子：
3.2
通讯作者：
Heinis, Christian
中科院分区：
文献类型：
--
作者：
Chen, Shiyu;Morales-Sanfrutos, Julia;Heinis, Christian
结构多样的肽大环组合文库为开发高亲和力配体提供了丰富的资源。在这项工作中，我们开发了用于产生遗传编码双环肽的连接体，并测试了由它们环化的肽是否在其主干构象中具有显着变化。两种新的环化试剂，每一个都含有三个硫醇反应基团，有效地和选择性地环化含有三个半胱氨酸部分的线性肽。当双环肽PK15的甲三烯连接体（Ki=2 nM）被新的连接体取代时，其抑制活性下降了1000多倍，这表明连接体对肽施加了不同的构象。事实上，溶液态核磁共振的结构分析揭示了三种双环肽的不同NOE约束，表明这些相对较小的双环肽结构中心连接物显著影响了肽的构象。这些结果证明了连接剂在肽大环中的突出结构作用，并表明以组合方式应用不同的环化连接剂可能是产生拓扑多样化的大环文库的一种有吸引力的方法。
Combinatorial libraries of structurally diverse peptide macrocycles offer a rich source for the development of high-affinity ligands to targets of interest. In this work we have developed linkers for the generation of genetically encoded bicyclic peptides and tested whether the peptides cyclised by them have significant variations in their backbone conformations. Two new cyclisation reagents, each containing three thiol-reactive groups, efficiently and selectively cyclised linear peptides containing three cysteine moieties. When the mesitylene linker of the bicyclic peptide PK15, a potent inhibitor of plasma kallikrein (Ki=2 nM), was replaced by the new linkers, its inhibitory activity dropped by a factor of more than 1000, suggesting that the linkers impose different conformations on the peptide. Indeed, structural analysis by solution-state NMR revealed different NOE constraints in the three bicyclic peptides, indicating that these relatively small linkers at the centres of bicyclic peptide structures significantly influence the conformations of the peptides. These results demonstrate the prominent structural role of linkers in peptide macrocycles and suggest that application of different cyclisation linkers in a combinatorial fashion could be an attractive means to generate topologically diverse macrocycle libraries.