engleski

ROLE OF PROTON MOVEMENT INSIDE GLUTAMIC ACID MOLECULE

Glutamic acid is one of the most important acids used in biosynthesis of proteins. In our study we measured FTIR spectrum of glutamic acid powder. The recorded spectrum is in accordance with well- known database spectrum of glutamic acid, but our extensive DFT calculations show that spectral band between 1900 and 3000 cm-1 does not originate from standard L-Glutamic acid conformation. We argue that this specific spectral band is associated with proton movement between the OH and NH2 groups. It is important to emphasize that our calculations show that one vibrational band corresponding to OH stretching strongly shifts by more than 1000 cm-1 to the lower part of vibrational spectrum. One of two OH groups is oriented towards NH2 group and its stretching band lowers due to proton movement. This kind of movement is lowering ground state energy of the Glutamic acid outside the dielectric medium, in which intermolecular hydrogen bonds flatten the structure and lower the energy. We give the typical conformation corresponding to this movement in graphical abstract.

Glutamic acid, FTIR, Proton movement, Quantum chemistry

nije evidentirano