Akademik Veri Yönetim Sistemi
INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, cilt.126, sa.8, 2026 (SCI-Expanded, Scopus)
In this study, we present detailed results on the molecular structure, vibrational frequencies, and bioactivity of the neutral L-Glu-L-Gln-L-Arg-L-Pro-L-Arg (EQRPR) pentapeptide, derived from rice bran, which exhibits anti-cancer, anti-Alzheimer's, and anti-obesity properties. Theoretical conformational analysis was performed to evaluate the conformational preferences of the pentapeptide. The most stable conformer was then optimized at the DFT/b3lyp/6-31G(d,p), DFT/b3lyp/6-31 + G(d,p), and DFT/wb97xd/6-31++G(d,p) levels of theory. The experimental FTIR and Raman spectra were compared with the theoretically predicted vibrational spectra at these levels. As the DFT/wb97xd/6-31++G(d,p) results showed the closest agreement with the experimental data, all subsequent calculations were performed using this level of theory. The molecular electrostatic potential (MEP) and frontier molecular orbitals were calculated using the optimized pentapeptide structure to evaluate its chemical reactivity. To investigate its potential biological activity as an anticancer and antiviral agent, molecular docking studies were performed against 1BNA, 4HJO, 1JV2, 3ZDX, 4WK0, 6 M03, 6 LU7, and 6VXX targets. Among these, the EQRPR pentapeptide exhibited the strongest binding affinity toward alpha 5 beta 1 integrin (4WK0; triangle G = -9.3 kcal/mol). Furthermore, following the docking calculations, the best conformation of the EQRPR-alpha 5 beta 1 integrin complex was subjected to 200 ns of all-atom molecular dynamics simulations. The MD results indicate the stability of the EQRPR-4WK0 complex, and the binding free energy was determined from the simulation results using the Molecular Mechanics/Poisson-Boltzmann Surface Area (MM-PBSA) method as -72.9895 kcal/mol. Overall, these results suggest that the neutral EQRPR pentapeptide possesses broad therapeutic potential and may serve as a promising candidate for the development of antiviral and anticancer agents.