Table 5.

Fluorescence Quantum Yields and Emission Maxima of Trp-cage peptides at pH 6.5.

Peptide and Substitutions	Yield b		λmax / nmc
	295 K	285 K	295 K	285 K
Trp-cage 16b a	0.010 ± 0.001	0.009 ± 0.001	342	343
Arg16Cit d	0.025 ± 0.002	0.016 ± 0.003	343	345
Asp9Ala	0.010 ± 0.003	ND e	336	ND
Asp9Leu	0.021 ± 0.004	0.019 ± 0.002	345	346
Asp9Leu / Arg16Ile	0.008 ± 0.003	0.0136 ± 0.0004	346	346
Asp9Ala / Arg16Nva d	0.014 ± 0.001	0.014 ± 0.001	343	343
Trp-cage 10b f
ΔSer20	0.023 ± 0.001	0.024 ± 0.001	348	349
Lys8Ala	0.0189 ± 0.0003	0.0168 ± 0.003	348	348
Asp9Glu	0.050 ± 0.006	0.043 ± 0.005	347	347
Asp9Glu / Arg16Lys	0.026 ± 0.002	ND	349	ND
Asp9Arg / Arg16Glu	0.033 ± 0.003	0.040 ± 0.002	347	346
Arg16Orn	0.037 ± 0.001	0.043 ± 0.001	349	348
Arg16Nva d	0.016 ± 0.002	ND	346	ND

^aDAFAQWLADaGPASaRPPPS, with the indicated substitutions for residues in bold font. All the Trp-cage peptides had Phe at position 3 and Trp at position 6.

^bFluorescence quantum yield at the indicated temperature (mean and standard deviation of 3 measurements).

^cEmission peak, ± 1 nm.

^dAbbreviations: Cit = citruline, Nva = norvaline.

^eND = Not determined.

^fDAFAQWLKDGGPASGRPPPS, with the indicated deletions or substitutions.