The gas phase conformers and vibrational spectra of valine, leucine and isoleucine: An ab initio study

Dokmaisrijan, Supaporn; Lee, Vannajan Sanghiran; Nimmanpipug, Piyarat

doi:10.1016/j.theochem.2010.04.033

Cited by 41 publications

(33 citation statements)

References 40 publications

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“…[38] In serine, the intramolecular H-bond exists between amino and hydroxyl groups of side chain in both cis and trans conformer. This is confirmed with earlier study by Dokmaisrijan et al [39]. They have also observed intramolecular H-bond between amino and hydroxyl groups in the most stable conformer.…”

Section: Resultssupporting

confidence: 92%

The Effect of Intramolecular H-Bond Interactions in the Isomerization Process in Amino Acids

Paranthaman

2018

J. Chil. Chem. Soc.

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The effect of intramolecular hydrogen bond (H-bond) interactions in the cis -trans isomerization of the amino acids such as, cysteine, serine, threonine and valine have been studied using density functional theory method. Our calculations have shown that the geometrical parameters are significantly changed during the isomerization process. This is due to the presence of intramolecular H-bonds within main chain or in between side chain and main chain. The barrier energies have been calculated for isomerization process in all the amino acids, which is more for cysteine and less for valine. The Fourier decomposition potential has been obtained for the above named amino acids which show that V 2 potential has higher value. The vibrational frequency analysis has been carried out for the cis and trans forms of cysteine, serine, threonine and valine amino acids and the results are discussed.

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Section: Resultssupporting

confidence: 92%

The Effect of Intramolecular H-Bond Interactions in the Isomerization Process in Amino Acids

Paranthaman

2018

J. Chil. Chem. Soc.

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“…Detailed assignments are also provided in Table 4. These VCD spectral peaks of ZW leucine disappear in the corresponding ROA spectrum, except for one strong negative ROA peak marked as 'A' at 1367 cm -1 that is due to the bending motions of the C (4)…”

Section: Amino Acids With Branched Chainsmentioning

confidence: 96%

A study of aliphatic amino acids using simulated vibrational circular dichroism and Raman optical activity spectra

Brunger

Wang

2013

Eur. Phys. J. D

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Vibrational optical activity (VOA) spectra, such as vibrational circular dichroism (VCD) andRaman optical activity (ROA) spectra, of aliphatic amino acids are simulated using density functional theory (DFT) methods in both gas phase (neutral form) and solution (zwitterionic form), together with their respective infrared (IR) and Raman spectra of the amino acids. The DFT models, which are validated by excellent agreements with the available experimental Raman and ROA spectra of alanine in solution, are employed to study other aliphatic amino acids. The inferred (IR) intensive region (below 2000 cm -1 ) reveals the signature of alkyl side chains, whereas the Raman intensive region (above 3000 cm -1 ) contains the information of the functional groups in the amino acids. Furthermore, the chiral carbons of the amino acids (except for glycine) dominate the VCD and ROA spectra in the gas phase, but the methyl group vibrations produce stronger VCD and ROA signals in solution. The C-H related asymmetric vibrations dominate the VOA spectra (i.e., VCD and ROA) > 3000 cm -1 reflecting the side chain structures of the amino acids. Finally the carboxyl and the C (2) H modes of aliphatic amino acids, together with the side chain vibrations, are very active in the VCD/IR and ROA/Raman spectra, which makes such the vibrational spectroscopic methods a very attractive means to study biomolecules.Keywords: Aliphatic amino acids, density functional theory calculations, vibrational optical activity, vibrational circular dichroism spectra, Raman optical activity spectra.

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“…Computational studies of neutral valine are much more limited (Stepanian et al, 1999; Lesarri et al, 2004; Yang et al, 2009; Dokmaisrijan, Lee, & Nimmanpipug, 2010; Bouchoux, Huang, & Inda, 2011). Investigation of the conformational landscape of neutral valine at the G3MP2B3 level places seven conformers in the first 5 kJ mol −1 range in the order of decreasing enthalpy: ValI C g− > ValII B g− > ValI C g+ > ValII A g− > ValII A a > ValIII C g+ ∼ ValI C a .…”

Section: Theoretical Protonation Thermochemistry Of Amino Acidsmentioning

confidence: 99%

Gas phase basicities of polyfunctional molecules. Part 3: Amino acids

Bouchoux

2011

Mass Spectrometry Reviews

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The present article is the third part of a general overview of the gas-phase protonation thermochemistry of polyfunctional molecules (first part: Mass Spectrom. Rev., 2007, 26:775-835, second part: Mass Spectrom. Rev., 2011, in press). This review is devoted to the 20 proteinogenic amino acids and is divided in two parts. In the first one, the experimental data obtained during the last 30 years using the equilibrium, thermokinetic and kinetic methods are presented. A general re-assignment of the values originating from these various experiments has been done on the basis of the commonly accepted Hunter & Lias 1998 gas-phase basicity scale in order to provide an homogeneous set of data. In the second part, theoretical investigations on gaseous neutral and protonated amino acids are reviewed. Conformational landscapes of both types of species were examined in order to provide theoretical protonation thermochemistry based on the truly identified most stable conformers. Proton affinities computed at the presently highest levels of theory (i.e. composite methods such as Gn procedures) are presented. Estimates of thermochemical parameters calculated using a Boltzmann distribution of conformers at 298K are also included. Finally, comparison between experiment and theory is discussed and a set of evaluated proton affinities, gas-phase basicities and protonation entropies is proposed.

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The gas phase conformers and vibrational spectra of valine, leucine and isoleucine: An ab initio study

Cited by 41 publications

References 40 publications

The Effect of Intramolecular H-Bond Interactions in the Isomerization Process in Amino Acids

The Effect of Intramolecular H-Bond Interactions in the Isomerization Process in Amino Acids

A study of aliphatic amino acids using simulated vibrational circular dichroism and Raman optical activity spectra

Gas phase basicities of polyfunctional molecules. Part 3: Amino acids

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