Unveiling the Neutral Forms of Glutamine

Abstract

Neutral glutamine has been evaporated by laser ablation of its solid sample to seed a rare gas carrier prior to a supersonic expansion and proved by Fourier transform microwave techniques. We report on three distinct neutral conformers that show a singular non‐interacting and flexible amide sidechain in contrast with the other proteinogenic aliphatic amino acids. It could explain the essential biological role of glutamine as a nitrogen source, and its unique ability to form a variety of hydrogen bonds with peptide backbones. Common computational methods fail to predict the delicate balance of intramolecular interactions controlling the geometry of the most stable conformer. The spectroscopic data here reported can be used to benchmark novel computational methods in quantum chemistry.

The eight structures of caffeic acid: a jet-cooled laser ablated rotational study

“…The Fourier transformation of the temporal prole of the emerging radiation yields rotational spectra of unprecedented resolution and sensitivity. These combined techniques have been established as an exceptionally robust tool to investigate the conformational landscape of many solid biomolecules [31][32][33][34][35] and, particularly, systems showing intricate conformational panoramas. [35][36][37][38][39][40] This experimental approach has been recently extended to the related trans-cinnamic and trans-p-coumaric phenolic acids.…”

Unveiling Five Naked Structures of Tartaric Acid

“…This strategy allowed us to unveil the natural and dominating conformations that compose TAs structural landscape, avoiding the vaporization issues. This experimental approach has proven ideal for exploring the architecture of numerous solid biomolecules of amino acids, [23] nucleosides, [24] sugars, [25] and dipeptides, [26] among others, constituting a definitive tool in the conformational analysis.…”