MRL-494 is an antibacterial agent and is a small-molecule inhibitor of β-barrel assembly machine A (BamA) impervious to efflux and the outer membrane permeability barrier.

By cellular thermal shift assay (CETSA), MRL-494 stabilizes BamA and BamAE470K from thermally induced aggregation, indicating direct or proximal binding to both BamA and BamAE470K. It is the altered activity of BamAE470K responsible for resistance to MRL-494. MRL-494 possesses a second mechanism of action that kills gram-positive organisms. In microbes lacking an OM, MRL-494 lethally disrupts the cytoplasmic membrane. The compound cannot disrupt the cytoplasmic membrane of gram-negative bacteria because it cannot penetrate the OM. Instead, MRL-494 inhibits OMP biogenesis from outside the OM by targeting BamA[1].