Paravizzini Samuel J, Hutton Craig A, Karas John A
School of Chemistry, The University of Melbourne, Parkville, VIC, 3010, Australia.
The Florey, 30 Royal Parade, Parkville, Victoria, 3052, Australia.
Chemistry. 2025 Aug 13;31(45):e01510. doi: 10.1002/chem.202501510. Epub 2025 Jul 29.
Fmoc solid-phase peptide synthesis has been indispensable for the efficient manufacture of research grade peptides and proteins, and peptide APIs. However, the solid-phase approach is still hampered by solubility issues and aggregation of the resin-bound peptide chain, which limits routine access to peptides > 40 amino acids in length. The use of backbone amide protecting groups, such as through the introduction of N-benzyl-based moieties and pseudoproline dipeptides, ameliorates this synthetic inefficiency somewhat. But benzyl groups can be difficult to remove postassembly, and pseudoprolines are limited to serine, threonine, and cysteine-rich peptide segments. To enhance the utility of backbone protection, we have evaluated the tetrahydropyranyl (Thp) group as a more acid labile alternative to benzyl protection. The Thp group can be efficiently introduced to the resin-bound peptide as a protected dipeptide and is readily cleaved and scavenged postsynthesis. A drastic improvement in the solid-phase assembly of aggregation-prone amyloid-β and prion-derived peptide fragments is observed using Thp as a backbone protecting group. We envisage that Thp-protected dipeptides will become useful building blocks for peptide manufacturing, complementing existing backbone protecting group strategies.
芴甲氧羰基（Fmoc）固相肽合成对于高效制备研究级肽、蛋白质及肽类活性药物成分（API）而言不可或缺。然而，固相合成方法仍受限于溶解性问题以及树脂结合肽链的聚集，这限制了常规获取长度超过40个氨基酸的肽。使用主链酰胺保护基，例如通过引入基于N - 苄基的部分和伪脯氨酸二肽，在一定程度上改善了这种合成效率低下的情况。但是苄基在组装后可能难以去除，并且伪脯氨酸仅限于富含丝氨酸、苏氨酸和半胱氨酸的肽段。为了提高主链保护的实用性，我们评估了四氢吡喃基（Thp）基团作为苄基保护的一种对酸更不稳定的替代方案。Thp基团可以作为受保护的二肽有效地引入到树脂结合的肽中，并且在合成后很容易被裂解和清除。使用Thp作为主链保护基时，观察到易聚集的淀粉样β肽和朊病毒衍生肽片段的固相组装有显著改善。我们设想，Thp保护的二肽将成为肽制造中有用的构建模块，补充现有的主链保护基策略。
