Conformational Modulation of in Vitro Activity of Cyclic RGD Peptides via Aziridine Aldehyde-Driven Macrocyclization Chemistry

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• 作者：脕ron Roxin ; Juan Chen ; Conor C. G. Scully ; Benjamin H. Rotstein ; Andrei K. Yudin ; Gang Zheng
• 刊名：Bioconjugate Chemistry
• 出版年：2012
• 出版时间：July 18, 2012
• 年：2012
• 卷：23
• 期：7
• 页码：1387-1395
• 全文大小：356K
• 年卷期：v.23,no.7(July 18, 2012)
• ISSN：1520-4812

文摘

Here, we demonstrate a conjugation strategy whereby cyclic RGD-containing macrocycles are prepared using aziridine aldehydes, isocyanides, and linear peptides, followed by conjugation to a cysteamine linker. Our method involves site-selective aziridine ring-opening with the nucleophilic sulfhydryl group of cysteamine. Fluorescein was then efficiently conjugated to the primary amine of cysteamine by NHS-chemistry. This strategy may be expanded to provide easy access to a wide variety of fluorescent dyes or radiometal chelators. Modeling studies showed that aziridine aldehyde cyclization chemistry stabilized the RGD motif into the required bioactive conformation and that this cyclization chemistry modulated the geometry of macrocycles of different residue lengths. In vitro studies showed that cPRGDA and cPRGDAA both selectively bound to 伪_V尾₃-overexpressing U87 glioblastoma cells, and that cPRGDA had a better binding affinity compared to cPRGDAA. The improved binding affinity of cPRGDA was attributed to the fixed Pro-C^伪-Asp-C^伪 distance surrounding the stabilized RGD motif in cPRGDA.