Critical Role of Position 10 Residue in the Polymyxin Antimicrobial Activity

Nitin A. Patil, Wendong Ma, Xukai Jiang, Xiaoji He, Heidi H. Yu, Hasini Wickremasinghe, Jiping Wang, Philip E. Thompson, Tony Velkov, Kade D. Roberts, Jian Li

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2 Citations (Scopus)


Polymyxins (polymyxin B and colistin) are lipopeptide antibiotics used as a last-line treatment for life-threatening multidrug-resistant (MDR) Gram-negative bacterial infections. Unfortunately, their clinical use has been affected by dose-limiting toxicity and increasing resistance. Structure-activity (SAR) and structure-toxicity (STR) relationships are paramount for the development of safer polymyxins, albeit very little is known about the role of the conserved position 10 threonine (Thr) residue in the polymyxin core scaffold. Here, we synthesized 30 novel analogues of polymyxin B1 modified explicitly at position 10 and examined the antimicrobial activity against Gram-negative bacteria and in vivo toxicity and performed molecular dynamics simulations with bacterial outer membranes. For the first time, this study revealed the stereochemical requirements and role of the β-hydroxy side chain in promoting the correctly folded conformation of the polymyxin that drives outer membrane penetration and antibacterial activity. These findings provide essential information for developing safer and more efficacious new-generation polymyxin antibiotics.

Original languageEnglish
Pages (from-to)2865–2876
Number of pages12
JournalJournal of Medicinal Chemistry
Issue number4
Publication statusPublished - 6 Feb 2023

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