Individual contributions of the aromatic chromophores to the near-UV Circular Dichroism in class A β-lactamases: A comparative computational analysis

Class A β-lactamases are enzymes which are responsible for the bacterial resistance against antibiotics and therefore are of great importance in rational inhibitor design. In this paper we comparatively analyze all the individual contributions of the aromatic chromophores in three class A β-lactamases (from Staphylococcus aureus, Streptomyces albus and Bacillus licheniformis) to their near-UV Circular Dichroism. The analysis is performed using recently developed procedure based on established theoretical method. We found that in β-lactamase from S. albus the most significant contributions to the total near-UV CD intensity exhibit Y251 and Y229. In the tryptophan-containing β-lactamases from B. licheniformis and S. albus, W229 and W251 express the strongest individual contributions. A comparative analysis of the individual contributions of conservative chromophores in class A enzymes namely W165, W210, W229, W251, Y97 and Y105 is presented.