Raman study of L-Asparagine and L-Glutamine molecules adsorbed on aluminum films in a wide frequency range

Abstract

Abstract. Using micro-Raman spectroscopy, a detailed study of vibrational spectra of L-Asparagine and L-Glutamine amino acids adsorbed on aluminum foils were carried out within the frequency range 80…3500 cm -1 under different excitation wavelengths. On the basis of detailed analysis of Raman spectra of the mentioned above amino acids and data of DFT-calculations of normal modes and isotopic substitution for these analytes available in literature, interpretation of amino acids vibrational bands were performed. The polarized Raman spectra of studied amino acids indicate different ordering of polycrystalline structure in distinct spots on the sample. The most significant variations of ratios between polarized bands are principally observed for deformation vibrations of NH 2 , COO -and CH 2 groups within entire "fingerprint" range and valence vibrations of CC and CN bonds within the range 1000…1100 cm -1 .

Signature molecular changes in the skeletal muscle of hindlimb unloaded mice

“…3B. Our experimental and the calculated Raman peaks agree well with the previous studies (6, 21, 22) within the uncertainty. However, the calculated spectra also show additional Raman bands which are, either very weak or indistinguishable in the experimentally obtained spectra.…”

“…Table 1 lists the calculated band positions for all the molecules. By comparing our results with the previous studies (6,21,22) and the calculated Raman spectra, the bands at 159 cm -1 , 223 cm -1 , 344 cm -1 , and 1209 cm -1 were allocated to asparagine,…”

Determination of the denaturation temperature of the Spike protein S1 of SARS-CoV-2 (2019 nCoV) by Raman spectroscopy

“…In Table 1 the number and percentage contribution of the AA-residues present in the GPS S1, is listed [22] . The aim has been to understand the Raman bands observed in terms of the number of AA units (residues, when forming the peptide chains) present and the intensity of vibrational modes appearing at a given wavenumber where a Raman band is observed [23] , [24] , [25] , [26] , [27] . However, special care has to be taken in establishing definitive identifications, because it is well known that in complex folded structures, as that occurring in proteins, different peptide sections in close physical proximity to each other, would affect the emission strength of some vibrational modes [24] , [25] , [26] , [27] .…”

Unveiling the Neutral Forms of Glutamine

“…In traditional studies in the condensed phase, strong intermolecular interactions fix glutamine as a doubly charged zwitterion, wiping out its conformational variability. So far, the few experiments to obtain any structural information are electron‐density projections, infrared and Raman studies, either in aqueous solutions or in crystal . In these condensed media, glutamine is in its zwitterionic form, that is, not the neutral form present in polypeptides chains.…”

“…So far, the few experiments to obtain any structural information are electron-density projections, [7] infrared and Raman studies, either in aqueous solutions or in crystal. [8][9][10][11][12][13] In these condensed media, glutamine is in its zwitterionic form, that is, not the neutral form present in polypeptides chains. The intrinsic conformational choices of amino acids can be revealed only when they are studied in isolation, where the neutral species present in polypeptide chains are the most stable in detriment of ionic or zwitterionic forms.…”