Sensing the anomeric effect in a solvent-free environment

摘要: The anomeric effect is a chemical phenomenon that refers to an observed stabilization of six-membered carbohydrate rings when they contain electronegative substituent at the C1 position ring. This stereo-electronic influences three-dimensional shapes many biological molecules, but its underlying physical origin still not clear. Cocinero et al. use combination laser spectroscopy and computational analysis create peptidic sensor can bind archetypal D-galactose in two different forms. Complexes formed between truncated peptide motif isolated gas phase are nearly identical structurally, although strength polarization their interactions with differs greatly. These results suggest it will be important re-evaluate influence, effects, substituents C2 rings. stereoelectronic unclear. Here shown complexes sugar structurally; however, It phenomenon1,2,3,4,5,6,7,8,9 stabilization10 molecules. manifested only this classical manner involving interaction endocyclic oxygen atom (O5) found such sugars (endo-anomeric effect) also through corresponding exocyclic O5 (exo-anomeric effect). However, origin(s) clear1,3,4,11,12,13,14. we show, using analysis, engage anomers phase, environment lacking extraneous factors which could confound analysis. (Anomers isomers differ orientation C1.) α- or β-anomers d-galactose Natural bond order calculations support observation, together reveal dominance exo- over endo-anomeric effect. As atoms positions (O1 O2, respectively) on pyranose ring alter exo/endo ratio carbohydrate, our sugars.