Jambunathan Kalyani, Galande Amit K
Center for Chemical Biology, SRI International, 140 Research Drive, Harrisonburg, VA 22802, USA.
Protein Pept Lett. 2014;21(1):32-8. doi: 10.2174/09298665113209990069.
Serum has a high intrinsic proteolytic activity that leads to continuous processing of peptides and proteins. Strategies to protect bioactive peptides from serum proteolytic degradation include incorporation of unnatural amino acids, conformational constraints, large polymeric tags, or other synthetic manipulations such as amide bond replacements. Here we explored a possibility of designing a serum stability tag made of natural amino acids. We observed that a diproline motif (-Pro-Pro-) shows remarkable stability against serum endopeptidases. Accordingly, we designed close to 50 peptides to identify natural amino acids flanking the -Pro-Pro- sequence that can enhance the serum stability of this motif. As a result, a tetrapeptide with the sequence Asp-Pro-Pro-Glu (DPPE) was identified that remains intact in human serum for more than 24 h. at 37°C.
血清具有很高的内在蛋白水解活性，会导致肽和蛋白质的持续加工。保护生物活性肽免受血清蛋白水解降解的策略包括掺入非天然氨基酸、构象限制、大型聚合物标签或其他合成操作，如酰胺键置换。在这里，我们探索了设计一种由天然氨基酸组成的血清稳定性标签的可能性。我们观察到二脯氨酸基序（-Pro-Pro-）对血清内肽酶具有显著的稳定性。因此，我们设计了近50种肽，以确定位于-Pro-Pro-序列两侧的能够增强该基序血清稳定性的天然氨基酸。结果，鉴定出一种序列为Asp-Pro-Pro-Glu（DPPE）的四肽，它在37°C的人血清中24小时以上保持完整。
