• vancomycin;
  • chloro-eremomycin;
  • cooperative effect;
  • ab initio QM;
  • divide-and conquer;
  • free energy


The cooperative effects between the binding of model bacterial cell wall termini and the dimer forms of the glycopeptide antibiotic vancomycin and chloro-eremomycin were investigated with conventional and divide-and-conquer (DC) ab initio quantum chemistry simulations. This feature is potentially important for drug design and controlling molecular recognition phenomena in these and other biochemical systems. In terms of the calculation, the vibrational contributions to the dimerization free energies of both molecules found to be the most costly and necessitated the use of the DC method. We specifically focused on calculating the relative strength of the cooperative effect for the two antibiotics. In good agreement with experiments, we find that the cooperative effect is stronger for chloro-eremomycin by about 1.39 kcal/mol. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010