Structure-activity relationships in human toll-like receptor 2-specific monoacyl lipopeptides

Deepak B. Salunke, Nikunj M. Shukla, Euna Yoo, Breanna M. Crall, Rajalakshmi Balakrishna, Subbalakshmi S. Malladi, Sunil A. David

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40 Scopus citations


Toll-like receptor 2-agonistic lipopeptides typified by S-[2,3-bis(palmitoyloxy)-(2RS)-propyl]-R-cysteinyl-S-serine (PAM 2CS) compounds are potential vaccine adjuvants. We had previously determined that at least one acyl group of optimal length (C 16) and an appropriately orientated ester carbonyl group is essential for TLR2-agonistic activity. We now show that these structurally simpler analogues display agonistic activities with human, but not murine, TLR2. SAR studies on the monoacyl derivatives show that the optimal acyl chain length is C 16, and aryl substituents are not tolerated. A variety of alkyl and acyl substituents on the cysteine amine were examined. All N-alkyl derivatives were inactive. In contradistinction, short-chain N-acyl analogues were found to be highly active, with a clear dependence on the chain length. A cysteine N-acetyl analogue was found to be the most potent (EC 50: 1 nM), followed by the N-butyryl analogue. The N-acetyl analogue is human TLR2-specific, with its potency comparable to that of PAM 2CS.

Original languageEnglish (US)
Pages (from-to)3353-3363
Number of pages11
JournalJournal of medicinal chemistry
Issue number7
StatePublished - Apr 12 2012


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