Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia.
Proc Natl Acad Sci U S A. 2010 Jun 29;107(26):11686-91. doi: 10.1073/pnas.1002498107. Epub 2010 Jun 11.
Recombinant proteins are important therapeutics due to potent, highly specific, and nontoxic actions in vivo. However, they are expensive medicines to manufacture, chemically unstable, and difficult to administer with low patient uptake and compliance. Small molecule drugs are cheaper and more bioavailable, but less target-specific in vivo and often have associated side effects. Here we combine some advantages of proteins and small molecules by taking short amino acid sequences that confer potency and selectivity to proteins, and fixing them as small constrained molecules that are chemically and structurally stable and easy to make. Proteins often use short alpha-helices of just 1-4 helical turns (4-15 amino acids) to interact with biological targets, but peptides this short usually have negligible alpha-helicity in water. Here we show that short peptides, corresponding to helical epitopes from viral, bacterial, or human proteins, can be strategically fixed in highly alpha-helical structures in water. These helix-constrained compounds have similar biological potencies as proteins that bear the same helical sequences. Examples are (i) a picomolar inhibitor of Respiratory Syncytial Virus F protein mediated fusion with host cells, (ii) a nanomolar inhibitor of RNA binding to the transporter protein HIV-Rev, (iii) a submicromolar inhibitor of Streptococcus pneumoniae growth induced by quorum sensing pheromone Competence Stimulating Peptide, and (iv) a picomolar agonist of the GPCR pain receptor opioid receptor like receptor ORL-1. This approach can be generally applicable to downsizing helical regions of proteins with broad applications to biology and medicine.
重组蛋白因其在体内具有强大、高度特异和无毒的作用而成为重要的治疗药物。然而，它们的生产成本很高，化学性质不稳定，而且给药困难，患者接受度和依从性低。小分子药物价格更便宜，生物利用度更高，但在体内的靶向特异性较低，并且常常伴有相关的副作用。在这里，我们通过采用赋予蛋白质效力和选择性的短氨基酸序列，并将其固定为化学和结构稳定且易于制备的小分子，来结合蛋白质和小分子的一些优势。蛋白质通常使用仅 1-4 个螺旋转弯（4-15 个氨基酸）的短α-螺旋与生物靶标相互作用，但如此短的肽在水中通常几乎没有α-螺旋性。在这里，我们表明，来自病毒、细菌或人类蛋白质的螺旋表位的短肽可以在水中被策略性地固定在高度α-螺旋结构中。这些螺旋约束化合物与具有相同螺旋序列的蛋白质具有相似的生物学效力。例如，（i）一种 picomolar 抑制剂，可以抑制呼吸道合胞病毒 F 蛋白介导的与宿主细胞融合，（ii）一种 nanomolar 抑制剂，可以抑制 RNA 与 HIV-Rev 转运蛋白的结合，（iii）一种 submicromolar 抑制剂，可以抑制肺炎链球菌生长诱导的群体感应信息素 Competence Stimulating Peptide，以及（iv）一种 picomolar 激动剂，可激活 GPCR 疼痛受体阿片受体样受体 ORL-1。这种方法可以普遍适用于缩小蛋白质的螺旋区域，在生物学和医学中有广泛的应用。
