Correlation of TrpGly and GlyTrp Rotamer Structure with W7 and W10 UV Resonance Raman Modes and Fluorescence Emission Shifts
Lowest-energy molecular conformers for tryptophan dipeptides in the zwitterion and anionic forms. (a) TrpGly, pH 5.5, stretched-out backbone conformer, (b) folded backbone conformer, (c) TrpGly, pH 9.3, (d) GlyTrp, pH 5.5, and (e) GlyTrp, pH 9.3. Atoms are color coded as follows: N, blue; O, red; H, yellow; C, grey. Dashed lines indicate electrostatic interactions discussed in the text.