Hintersteiner Martin, Knox Andrew J, Mudd Gemma, Auer Manfred
Novartis Institutes for BioMedical Research Basel, Novartis Campus, Fabrikstrasse 10, 4056 Basel, Switzerland.
J Chem Biol. 2012 Apr;5(2):63-79. doi: 10.1007/s12154-011-0071-9. Epub 2012 Jan 3.
An array of chemical modifications have recently emerged, designed to improve the stability of natural peptides that inherently suffer from short in vivo half-lives, thereby preventing their use as therapeutics. The resultant peptidomimetics resemble native peptides; however, they contain synthetic elements (e.g. non-coded amino acids) which confer improved biophysical properties. An elegant approach towards the identification of peptidomimetics is through screening of large combinatorial chemical libraries incorporating both coded and non-coded amino acids (e.g. β amino acids). We apply here our recently developed Integrated Chemical Biophysics (ICB) platform, which combines microscale one-bead one-compound screening with fluorescence tagging of retrieved hit beads and subsequent affinity determination of hit compounds in homogenous solution, to the task of identifying novel mixed α, β peptidomimetic binders for the adaptor protein SLAM-associated protein (SAP), which acts as an intracellular adapter that transduces T and NK cell activation. An enhancement to the ICB process is introduced which enables ranking hit compounds from single-point measurements even if the library compound is <95% pure and without HPLC purification of single-bead-derived substance. Finally, a novel computational protocol enabling binding mode and SAR rationalisation of hit compounds is also described which we now utilise to inform future library design. Application of the full ICB process has allowed identification of a highly interesting motif, Ac-β(3)-Pro-α-pTyr, as a mimic for the -1 and -2 positions of the natural binding motif and provides a promising starting point for further optimization towards higher-affinity SAP inhibitors with enhanced metabolic stability.
The online version of this article (doi:10.1007/s12154-011-0071-9) contains supplementary material, which is available to authorized users.
最近出现了一系列化学修饰方法，旨在提高天然肽的稳定性，这些天然肽在体内半衰期较短，因此无法用作治疗药物。由此产生的肽模拟物类似于天然肽；然而，它们包含合成元素（例如非编码氨基酸），这些元素赋予了更好的生物物理性质。一种识别肽模拟物的巧妙方法是通过筛选包含编码和非编码氨基酸（例如β氨基酸）的大型组合化学文库。我们在此应用我们最近开发的集成化化学生物物理学（ICB）平台，该平台将微尺度单珠单化合物筛选与回收的命中珠子的荧光标记以及随后在均相溶液中对命中化合物的亲和力测定相结合，用于识别衔接蛋白信号淋巴细胞激活分子相关蛋白（SAP）的新型混合α，β肽模拟物结合剂，SAP作为一种细胞内衔接蛋白，可转导T细胞和NK细胞的激活。引入了对ICB过程的一种改进，即使文库化合物纯度低于95%且无需对单珠来源物质进行HPLC纯化，也能够通过单点测量对命中化合物进行排名。最后，还描述了一种新颖的计算方案，可实现对命中化合物的结合模式和SAR合理化，我们现在利用该方案为未来的文库设计提供参考。完整的ICB过程的应用使得能够识别出一个非常有趣的基序Ac-β(3)-Pro-α-pTyr，作为天然结合基序-1和-2位置的模拟物，并为进一步优化以获得具有更高代谢稳定性的高亲和力SAP抑制剂提供了一个有前景的起点。
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