Department of Experimental and Health Science, Universitat Pompeu Fabra, Barcelona Biomedical Research Park, Barcelona, 08003, Spain.
Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, 1649-028, Portugal.
J Pept Sci. 2019 Aug;25(8):e3195. doi: 10.1002/psc.3195.
Ctn[15-34], a downsized version of the snake venom cathelicidin-like peptide crotalicidin (Ctn), shows an unusually high lifespan (t , approximately 12 h) in human serum, which significantly adds to its promise as an antimicrobial and antitumor agent. Herein we investigate the role of Ctn[15-34] structure on serum survival. Using a set of analogs, we show that C-terminal amidation, as well as the specific layout of the Ctn[15-34] sequence-a helical N-terminal domain followed by a hydrophobic domain-is crucial for slow degradation, and any change in their arrangement results in significantly lower t . Aside from the privileged primary structure, features such as self-aggregation can be ruled out as causes for the long serum life. Instead, studies in other protease-rich fluids suggest a key role for certain human serum components. Finally, we demonstrate that Ctn[15-34] is able to induce bacterial death even after 12-hour pre-incubation in serum, in agreement with the proteolytic data. Altogether, the results shed light on the uncommon stability of Ctn[15-34] in human serum and confirm its potential as an anti-infective lead.
Ctn[15-34] 是蛇毒抗菌肽 cathelicidin-like 肽 crotalicidin 的缩小版，在人血清中表现出异常长的半衰期（t ，约 12 小时），这使其作为一种抗菌和抗肿瘤药物的前景更加广阔。在此，我们研究了 Ctn[15-34] 结构对血清存活的作用。使用一组类似物，我们表明 C 末端酰胺化以及 Ctn[15-34] 序列的特定布局——螺旋状 N 端结构域后跟疏水性结构域——对于缓慢降解至关重要，任何排列的改变都会导致半衰期显著降低。除了优先的一级结构外，诸如自聚集等特征可以排除是导致长血清寿命的原因。相反，在其他富含蛋白酶的液体中的研究表明，某些人血清成分起着关键作用。最后，我们证明 Ctn[15-34] 在血清中预孵育 12 小时后仍能诱导细菌死亡，这与蛋白酶数据一致。总的来说，这些结果揭示了 Ctn[15-34] 在人血清中异常稳定的原因，并证实了其作为抗感染先导物的潜力。
