Biophysical Society Thematic Meeting | Stockholm 2022

Physical and Quantitative Approaches to Overcome Antibiotic Resistance

Wednesday Speaker Abstracts

THE ADAPTIVE SUCCESS OF NEW DELHI METALLO-BETA-LACTAMASE DEPENDS ON THE IN-CELL KINETIC PROTEIN STABILITY

Alejandro J Vila ; Lisandro J Gonzalez 1 ; Guillermo Bahr 1 ; 1 University of Rosario - CONICET, IBR, Rosario, Argentina 2 Case Western Reserve University, VACLE, Cleveland, OH, USA

Protein stability is essential for biological function. In contrast to the vast knowledge on the thermodynamics of protein stability in vitro, little is known about the factors governing the kinetic stability, that defines the lifetime of the native state of proteins within the cell. Here we show that the kinetic stability of the metallo- β -lactamase NDM-1 in the bacterial periplasm is optimized to face metal restriction at the host-pathogen interface. NDM-1 is one of the main responsible of providing resistance to carbapenems in pathogenic bacteria. Despite its high stability in vitro, the non-metalated (apo) NDM-1 is recognized and proteolyzed by the protease Prc due to the flexibility of its C-terminal domain. Zn(II) binding renders the protein refractory to degradation by quenching this flexibility. Apo-NDM-1 is anchored to the outer membrane, a localization that renders it less accessible to Prc and less prone to aggregate. Membrane anchoring also protects apo-NDM-1 from the quality control protease DegP, which degrades misfolded, non-metalated NDM-1 precursors. More recent clinical variants of NDM accumulate mutations at the C-terminus that quench its flexibility therefore enhancing their stability towards proteolysis. This work provides direct evidence of how the kinetic stability of a protein optimized within the bacterial cell, and links metallo- β -lactamase-mediated resistance with the cellular metabolism in the periplasm. On a broader perspective, this reveals that knowledge of the protein physiology in the cell is essential to understand protein kinetic stability.

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