Correlation of TrpGly and GlyTrp Rotamer Structure with W7 and W10 UV Resonance Raman Modes and Fluorescence Emission Shifts

Table 1

Fluorescence emission maxima, experimental and calculated W10 band peaks and W7 Fermi doublet band ratio, 𝐼(1360 cm⁻¹)/𝐼(1340 cm⁻¹), for GW and WG dipeptides at pH 5.5 and 9.3. Parenthetical values are for shifts relative to values for the WG zwitterion species.

Peptide, pH	Experimental W10 Raman Shift (cm^−1)	Calculated W10 Raman Shift (cm^−1)	W7 𝐼(1360cm^−1)/𝐼(1340cm^−1)	Fluorescence emission (nm)
WG, 5.5	1242	1271	1.0	347
WG, 9.3	1239 (−3)	1267 (−4)	1.4	355 (+8)
GW, 5.5	1235 (−7)	1268 (−3)	1.6	357 (+10)
GW, 9.3	1236 (−6)	1262 (−9)	1.6	357 (+10)