Hydrogen bonds in crystalline D-alanine
What is it about?
Enantiomeric amino acids have specific physiological functions in complex biological systems. Systematic studies focusing on the solid-state properties of D-amino acids are, however, still limited. To shed light on this field, structural and spectroscopic studies of D-alanine using neutron powder diffraction, polarized Raman scattering and ab initio calculations of harmonic vibrational frequencies were carried out. Clear changes in the number of vibrational modes are observed as a function of temperature, which can be directly connected to variations of the N—D bond lengths. These results reveal dissimilarities in the structural properties of D-alanine compared with L-alanine.
Why is it important?
This work is motivated by the fact that D-Amino acids, the enantiomers of L-amino acids, are increasingly being recognized as physiologically active molecules as well as potential biomarkers. Nonetheless, the solid-state properties of the two enantiomers have not been fully investigated to date.