Not only ClpC1 but also ClpX are drug targets of Ilamycins

Abstract

AbstractThe mycobacterial caseinolytic protease (Clp) system has been recognized as a promising therapeutic target. A group of natural cyclic peptides including ilamycins, are traditionally thought to target the ClpC1 component of the ClpC1P1P2 proteasome. However, our study reveals that not only ClpC1 but also ClpX can be targeted by ilamycins. Specifically, ilamycin E (ILE) and ilamycin F (ILF) demonstrated superior delayed mycobactericidal activities compared to other ilamycin components. We identified a unique mutation inclpXand a novel insertion inclpC1, both of which confer resistance to ILE and ILF in mycobacteria, as confirmed through gene editing. Crucially, we found that ILE significantly disrupts the proteolytic functions of both the ClpXP1P2 and ClpC1P1P2 complexes. This is the first report highlighting ClpX as a critical target for mycobacterial killing, alongside ClpC1. Our findings emphasize the potential of ilamycins to target multiple components of the Clp protease system, offering a novel dual-target strategy for combating mycobacterial infections.