Structural, Energetic, and Spectral Analysis of a Model Peptide and its Isomers
Primary Investigator (PI) Name
Martina Kaledin
Department
CSM - Chemistry and Biochemistry
Abstract
Formamide is a planar structure, the simplest molecule with a peptide bond. It can be utilized as a model for understanding more complex peptides. Formamide has been linked to the study of the origin of life and is regarded to be a possible precursor for prebiotic chemistry. The primary motivation of this work is to understand the potential energy surface (PES) landscape, identify many plausible dissociation channels, and describe the vibrational characteristics of formamide beyond the harmonic approximation. We confirmed the previously known high-energy tautomerization of formamide into formimidic acid and formimidic acid into other isomers. The normal mode analysis is used to calculate harmonic frequencies. Anharmonicities are also evaluated using vibrational perturbation theory (VPT2), vibrational self-consistent field (VSCF), and variational configuration interaction (VCI). These theoretical methods shed light on the impact of anharmonicity on characteristic peptide vibrations, such as amide A, I, and II vibrational modes. Later, the quality of the PES fitting technique was tested by Hashem et al. [J. Chem. Theory Comput. 19 (2023) 5690-5700] using optimized molecular geometries of multiple stational points found in this work.
Disciplines
Computational Chemistry | Physical Chemistry
Structural, Energetic, and Spectral Analysis of a Model Peptide and its Isomers
Formamide is a planar structure, the simplest molecule with a peptide bond. It can be utilized as a model for understanding more complex peptides. Formamide has been linked to the study of the origin of life and is regarded to be a possible precursor for prebiotic chemistry. The primary motivation of this work is to understand the potential energy surface (PES) landscape, identify many plausible dissociation channels, and describe the vibrational characteristics of formamide beyond the harmonic approximation. We confirmed the previously known high-energy tautomerization of formamide into formimidic acid and formimidic acid into other isomers. The normal mode analysis is used to calculate harmonic frequencies. Anharmonicities are also evaluated using vibrational perturbation theory (VPT2), vibrational self-consistent field (VSCF), and variational configuration interaction (VCI). These theoretical methods shed light on the impact of anharmonicity on characteristic peptide vibrations, such as amide A, I, and II vibrational modes. Later, the quality of the PES fitting technique was tested by Hashem et al. [J. Chem. Theory Comput. 19 (2023) 5690-5700] using optimized molecular geometries of multiple stational points found in this work.