Computational prediction of the preferred glycation sites of model helical peptides derived from human serum albumin (HSA) and lysozyme helix 4 (LH4)

The preferred glycation sites of model helical peptides derived from human serum albumin and lysozyme helix 4 have been established by resorting to the calculation of some conceptual DFT descriptors like the Fukui function indexes, the condensed dual descriptor Delta f (r) and the electrophilic and nucleophilic Parr functions. The results were obtained within the framework of QM:MM calculations performed through the ONIOM method in the presence of water as a solvent. For the sake of comparison, additional calculations were done on a model beta-hairpin peptide (TIMP2). The pKa's of the different lysine residues can be qualitatively predicted on the light of the obtained values for the conceptual DFT descriptors.