ADEP1 activated ClpP1P2 macromolecule of Leptospira, an ideal Achilles' heel to deregulate proteostasis and hamper the cell survival

Abstract

The caseinolytic protease (ClpP) complex in Leptospira interrogans is unusual in its functional activation. The genus Leptospira has two ClpPs, ClpP1 and ClpP2, which transcribes independently, regardless it couples to form the active tetradecamer. Acyldepsipeptide (ADEP) antibiotic hampers the growth of numerous bacterial species by activating the target protein ClpP and dysregulating the physiological proteostasis within the cell. In vitro culture of the L. interrogans fortified with the ADEP impeded the spirochete growth accompanied by a more elongated morphology. The chemoactivation of the ClpP is conditional on the duration of the self-compartmentalization of each of the ClpP isoforms. The small extent (10 min) self-assembled ClpP1P2 revealed inhibition in the peptidase activity (7-fold) in the presence of the ADEP due to the self-cleavage of the ClpP subunits. On supplementation of the {beta}-casein or bovine serum albumin, the peptidase activity of the ClpP1P2 (short-incubated) got enhanced by the ADEP, while the ClpP1P2 (long-incubated) activity was retained to the same level. ADEP can also switch on the ClpP1P2 from a strict peptidase into proteolytic machinery that discerns and degrades the unfolded protein substrates autonomous of the cognate chaperone ClpX. In consensus to the most prokaryotes with the multi ClpP variants, the computational prototype of the ClpP1P2 tertiary structure infers that the hydrophobic pocket wherein the ADEPs predominantly docks are present in the ClpP2 heptamer. Additionally, the dynamic light scattering and the site-directed mutagenesis of a catalytic serine residue in either of the ClpP isoforms proposes a second interaction site for the ADEP.