Comparison of Structural Types of Proline Pentamer by Quantum Chemical Calculation (QCC)

• Published in: International Journal of Advanced Culture Technology(IJACT) Vol. 11; no. 2; pp. 323 - 329
• Main Author: Jae-Ho Sim
• Format: Journal Article
• Language: English
• Published: 국제문화기술진흥원 30.06.2023
• Subjects: 과학기술학; Structural Optimization; Quantum Chemical Calculation (QCC); Oligopeptide; Proline Pentamer; Conformation
• ISSN: 2288-7202; 2288-7318
• DOI: 10.17703/IJACT.2023.11.2.323

In this study, Proline pentamer model was used to investigate change in the dihedral angle, intramolecular hydrogen bonding and formation energies during structural optimization. L-Proline (LP, as an imino acid residue) pentamers having four conformation types [β: φ/ψ=t−/t+, α: φ/ψ=g−/g−, PPII: φ/ψ=g−/t+ and P-like: φ/ψ= g−/g+] were carried out by QCC [B3LYP/6-31G(d,p)]. The optimized structure and formation energy were examined for designated structure. In LP, P-like and PPII types did not change by optimization, and β types were transformed into PPII having no H-bond independently of the designated ψ values. PPII was more stable than P-like by about 2.2 kcal/mol/mu. The hydrogen bond distances of d2(4-6) type H-bonds were 1.94 - 2.00Å. In order to understand the processes of the transformations, the changes of φ/ψ, distances of NH-OC (dNH/CO) and formation energies (ΔE, kcal/mol/mu) were examined.