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

► Ten models of cyclic RGD pentapeptides have been studied at B3LYP/6-311G(d,p) level. ► All the 10 models were fully optimized both in the gas phase and in the solvent. ► The modified models of cRGDEf and cRGDCf might be candidates for the active cyclic RGD pentapeptides.