State Key Laboratory of Structural Chemistry and Danish-Chinese Centre for Proteases and Cancer, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian, 350002, P.R. China.
Department of Molecular Biology and Genetics, Aarhus University, Aarhus, 8000, Denmark.
Int J Biol Sci. 2017 Sep 21;13(10):1222-1233. doi: 10.7150/ijbs.21597. eCollection 2017.
This review summarizes our studies in the development of small cyclic peptides for specifically modulating enzyme activity. Serine proteases share highly similar active sites but perform diverse physiological and pathological functions. From a phage-display peptide library, we isolated two mono-cyclic peptides, upain-1 (CSWRGLENHRMC) and mupain-1 (CPAYSRYLDC), which inhibit the activity of human and murine urokinase-type plasminogen activators (huPA and muPA) with values in the micromolar or sub-micromolar range, respectively. The following affinity maturations significantly enhanced the potencies of the two peptides, 10-fold and >250-fold for upain-1 and mupain-1, respectively. The most potent muPA inhibitor has a potency ( = 2 nM) and specificity comparable to mono-clonal antibodies. Furthermore, we also found an unusual feature of mupain-1 that its inhibitory potency can be enhanced by increasing the flexibility, which challenges the traditional viewpoint that higher rigidity leading to higher affinity. Moreover, by changing a few key residues, we converted mupain-1 from a uPA inhibitor to inhibitors of other serine proteases, including plasma kallikrein (PK) and coagulation factor XIa (fXIa). PK and fXIa inhibitors showed values in the low nanomolar range and high specificity. Our studies demonstrate the versatility of small cyclic peptides to engineer inhibitory potency against serine proteases and to provide a new strategy for generating peptide inhibitors of serine proteases.
本文综述了我们在开发用于特异性调节酶活性的小环肽方面的研究。丝氨酸蛋白酶具有高度相似的活性部位，但具有不同的生理和病理功能。从噬菌体展示肽文库中，我们分离到两种单环肽，upain-1（CSWRGLENHRMC）和 mupain-1（CPAYSRYLDC），它们分别以微摩尔或亚微摩尔范围内的 值抑制人源和鼠源尿激酶型纤溶酶原激活剂（huPA 和 muPA）的活性。随后的亲和力成熟显著提高了这两种肽的效力，upain-1 和 mupain-1 的效力分别提高了 10 倍和 >250 倍。最有效的 muPA 抑制剂的效力（ = 2 nM）和特异性可与单克隆抗体相媲美。此外，我们还发现了 mupain-1 的一个不寻常特性，即其抑制效力可以通过增加灵活性来增强，这挑战了刚性更高导致亲和力更高的传统观点。此外，通过改变几个关键残基，我们将 mupain-1 从 uPA 抑制剂转变为其他丝氨酸蛋白酶的抑制剂，包括血浆激肽释放酶（PK）和凝血因子 XIa（fXIa）。PK 和 fXIa 抑制剂的 值在纳摩尔范围内，具有高特异性。我们的研究表明，小环肽具有多样性，可以设计针对丝氨酸蛋白酶的抑制效力，并为生成丝氨酸蛋白酶的肽抑制剂提供了新策略。
