Quantum chemical study of molecular properties of small branched-chain amino acids in water
Abstract Four aliphatic amino acids—α-aminobutyric acid (AABA), β-aminobutyric acid (BABA), α-aminoisobutyric acid (AAIBA) and β-aminoisobutyric acid (BAIBA) were investigated in water as a solvent by two quantum chemical methods. B3LYP hybrid version of DFT was used for geometry optimization and a...
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| Language: | English |
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Springer
2025-01-01
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| Series: | Amino Acids |
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| Online Access: | https://doi.org/10.1007/s00726-024-03437-y |
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| author | Roman Boča Žofia Rádiková Juraj Štofko Beata Vranovičová Cyril Rajnák |
| author_facet | Roman Boča Žofia Rádiková Juraj Štofko Beata Vranovičová Cyril Rajnák |
| author_sort | Roman Boča |
| collection | DOAJ |
| description | Abstract Four aliphatic amino acids—α-aminobutyric acid (AABA), β-aminobutyric acid (BABA), α-aminoisobutyric acid (AAIBA) and β-aminoisobutyric acid (BAIBA) were investigated in water as a solvent by two quantum chemical methods. B3LYP hybrid version of DFT was used for geometry optimization and a full vibrational analysis of neutral molecules, their cations and anions in the canonical and zwitterionic forms (6 forms for each species). Ab initio DLPNO-CCSD(T) method was applied in the geometry pre-optimized by B3LYP. Calculated molecular descriptors involve dipole moment, quadrupole moment, dipole polarizability, energy of zero-point vibration and total entropic term which enter the standard Gibbs energy. In addition, a set of collective electronic and thermodynamic properties associated with redox process were evaluated: ionization energy, electron affinity, chemical hardness, molecular electronegativity, electrophilicity index, absolute oxidation and reduction potentials. A mutual comparison of these structural isomers including γ-aminobutyric acid (GABA) shows high degree of similarity in molecular descriptors. However, cluster analysis of 12 electro neutral, linear and branched amino acids with 2 – 6 carbon atoms discriminates them into five clusters. It is found that the electrophilicity index correlates with the absolute reduction potential along a straight line (24 items). The reduction potential for canonical structure varies between 1.21 V (glycine) and 1.45 V (AABA) whereas for the zwitterionic form it is visibly lower 0.52–1.11 V. The highest absolute reduction potential > 1.43 V is shown by α-amino acids: α-alanine, AABA (homoalanine) and AAIBA having 2-methyl or 2-ethyl functional group. The calculated absolute oxidation potential correlates with the adiabatic ionization energy and can be used as a criterion of the antioxidant capacity. According to thermodynamic data, the SPLET mechanism of the electron-proton coupled transfer is favored over the alternative SET-PT mechanism. This work contributes to the creation of a database of molecular properties of amino acids based on the same method and basis set. |
| format | Article |
| id | doaj-art-d394959f6a4e48c39b3ac52afe607712 |
| institution | Kabale University |
| issn | 1438-2199 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | Springer |
| record_format | Article |
| series | Amino Acids |
| spelling | doaj-art-d394959f6a4e48c39b3ac52afe6077122025-01-19T12:28:19ZengSpringerAmino Acids1438-21992025-01-0157111310.1007/s00726-024-03437-yQuantum chemical study of molecular properties of small branched-chain amino acids in waterRoman Boča0Žofia Rádiková1Juraj Štofko2Beata Vranovičová3Cyril Rajnák4Faculty of Health Sciences, University of SS Cyril and MethodiusFaculty of Health Sciences, University of SS Cyril and MethodiusFaculty of Health Sciences, University of SS Cyril and MethodiusFaculty of Natural Sciences, University of SS Cyril and MethodiusFaculty of Natural Sciences, University of SS Cyril and MethodiusAbstract Four aliphatic amino acids—α-aminobutyric acid (AABA), β-aminobutyric acid (BABA), α-aminoisobutyric acid (AAIBA) and β-aminoisobutyric acid (BAIBA) were investigated in water as a solvent by two quantum chemical methods. B3LYP hybrid version of DFT was used for geometry optimization and a full vibrational analysis of neutral molecules, their cations and anions in the canonical and zwitterionic forms (6 forms for each species). Ab initio DLPNO-CCSD(T) method was applied in the geometry pre-optimized by B3LYP. Calculated molecular descriptors involve dipole moment, quadrupole moment, dipole polarizability, energy of zero-point vibration and total entropic term which enter the standard Gibbs energy. In addition, a set of collective electronic and thermodynamic properties associated with redox process were evaluated: ionization energy, electron affinity, chemical hardness, molecular electronegativity, electrophilicity index, absolute oxidation and reduction potentials. A mutual comparison of these structural isomers including γ-aminobutyric acid (GABA) shows high degree of similarity in molecular descriptors. However, cluster analysis of 12 electro neutral, linear and branched amino acids with 2 – 6 carbon atoms discriminates them into five clusters. It is found that the electrophilicity index correlates with the absolute reduction potential along a straight line (24 items). The reduction potential for canonical structure varies between 1.21 V (glycine) and 1.45 V (AABA) whereas for the zwitterionic form it is visibly lower 0.52–1.11 V. The highest absolute reduction potential > 1.43 V is shown by α-amino acids: α-alanine, AABA (homoalanine) and AAIBA having 2-methyl or 2-ethyl functional group. The calculated absolute oxidation potential correlates with the adiabatic ionization energy and can be used as a criterion of the antioxidant capacity. According to thermodynamic data, the SPLET mechanism of the electron-proton coupled transfer is favored over the alternative SET-PT mechanism. This work contributes to the creation of a database of molecular properties of amino acids based on the same method and basis set.https://doi.org/10.1007/s00726-024-03437-yB3LYPDLPNO-CCSD(T)2-amino(iso)butyric acids3-amino(iso)butyric acids |
| spellingShingle | Roman Boča Žofia Rádiková Juraj Štofko Beata Vranovičová Cyril Rajnák Quantum chemical study of molecular properties of small branched-chain amino acids in water Amino Acids B3LYP DLPNO-CCSD(T) 2-amino(iso)butyric acids 3-amino(iso)butyric acids |
| title | Quantum chemical study of molecular properties of small branched-chain amino acids in water |
| title_full | Quantum chemical study of molecular properties of small branched-chain amino acids in water |
| title_fullStr | Quantum chemical study of molecular properties of small branched-chain amino acids in water |
| title_full_unstemmed | Quantum chemical study of molecular properties of small branched-chain amino acids in water |
| title_short | Quantum chemical study of molecular properties of small branched-chain amino acids in water |
| title_sort | quantum chemical study of molecular properties of small branched chain amino acids in water |
| topic | B3LYP DLPNO-CCSD(T) 2-amino(iso)butyric acids 3-amino(iso)butyric acids |
| url | https://doi.org/10.1007/s00726-024-03437-y |
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