Free Energy Decomposition of CarO Outer Membrane Protein of Acinetobacter baumannii

The increase in the number of antibiotic-resistant microorganisms reported today has made this issue one of the main topics of all institutes. Acineteobacter baumanni is a species that is on the list of the WHO and plays an important role, especially in hospital-acquired infections. CarO outer membrane protein, which regulates the passage of small molecules and some antibiotics into the periplasmic space and is associated with carbapenem resistance, has been identified in A. baumannii. In this study, residues that contribute to the binding energy of imipenem to different types of CarO proteins were identified. In addition, energy decomposition was compared when Biapenem, Ertapenem, Imipenem, Faropenem, and Meropenem were docked to ATCC-17978 CarO protein separately. As a result of this study, it was determined that generally charged residues had a negative effect on binding affinity, but hydrophobic and uncharged residues had a positive effect. In addition, in ertapenem, faropenem, and meropenem-bound complexes, charged residues increased the affinity and caused the interaction between carbapenems and CarO to be continuous and tight. It was predicted that the residues determined in this study would be precursors to mutagenesis studies and could also be an example for similar studies.