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Structure–activity studies on polymyxin derivatives carrying three positive charges only reveal a new class of compounds with strong antibacterial activity

2017; Elsevier BV; Volume: 91; Linguagem: Inglês

10.1016/j.peptides.2017.03.002

1873-5169

Martti Vaara, Timo Vaara, Jonathan M. Tyrrell,

Pneumocystis jirovecii pneumonia detection and treatment

Recent years have brought in an increased interest to develop improved polymyxins. The currently used polymyxins, i.e. polymyxin B and colistin (polymyxin E) are pentacationic lipopeptides that possess a cyclic heptapeptide part with three positive charges, a linear "panhandle" part with two positive charges, and a fatty acyl tail. Unfortunately, their clinical use is shadowed by their notable nephrotoxicity. We have previously developed a polymyxin derivative NAB739 which lacks the positive charges in the linear part. This derivative is better tolerated than polymyxin B in cynomolgus monkeys and is, in contrast to polymyxin B, excreted into urine in monkeys and rats. Here we have conducted further structure-activity relationship (SAR) studies on 17 derivatives with three positive charges only. We discovered a remarkably antibacterial class, as exemplified by NAB815, that carries two positive charges only in the cyclic part.