valinomycin

Valinomycin is a naturally occurring cyclododecadepsipeptide ionophore antibiotic produced by Streptomyces fulvissimus and related Streptomyces species[1][4][6]. It consists of three units each of L-valine, D-valine, D-alpha-hydroxyisovaleric acid, and L-lactic acid linked alternately to form a 36-membered macrocyclic ring[1][6]. Valinomycin acts as a highly selective potassium ion transporter across lipid membranes, facilitating the movement of K⁺ ions down their electrochemical gradient while excluding sodium ions due to its structural selectivity[4][7]. This disrupts cellular ionic balance and can induce cell death through membrane depolarization. Its primary use is as a biochemical tool in research; it has also demonstrated potent antiviral activity in vitro (e.g., against SARS-CoV)[3], but its high toxicity limits therapeutic application. Valinomycin is extremely toxic to mammals as well as bacteria due to its non-selective disruption of cellular ionic gradients[5][7].

Other names

potassium ionophore Ivalinomicinvalino