In search of active RGD peptides: Theoretical study of hydrogen bonding in five-member ring cyclic-RGD isomers

Molecular structures, properties and hydrogen bonding in 10 models of cyclic-five-member-ring pentapeptides containing Arginine–Glycine–Aspartic acid (RGD) have been studied at B3LYP/6-311G(d,p) theoretical level. Among the investigated models, five structures represent active RGD peptides (cRGDfV, cRGDfE, cRGDfC, cRGDyV, and cRGDfK). The other five models were derived from the active structures by exchanging the positions of the fourth residue and the fifth residue of the corresponding active model. All the 10 models were fully optimized both in the gas phase and in the solvent. The comparison of the predicted characteristics suggests that the modified models of cRGDEf and cRGDCf might be good candidates for the active cyclic RGD pentapeptides.