Table 1.

Folding thermodynamics of peptides 1–7 from NMR measurements^a

Peptide	Δδ Gly10 Hα/Hα′ (ppm)	Fraction Folded (%)	ΔGfold (kcal mol−1)	ΔΔGfold vs. 1 (kcal mol−1)
1	0.20	65	−0.3
2	0.26	83	−0.9	−0.6
3	0.12	39	+0.2	+0.5
4		37 b	+0.3	+0.6
4trans (60%)	0.19	61	−0.3	+0.0
4cis (40%)	0.09
5		19b	+0.8	+1.1
5trans (76%)	0.09	30	+0.5	+0.8
5cis (24%)	0.00
6		29b	+0.5	+0.8
6trans (65%)	0.12	38	+0.3	+0.6
6cis (35%)	0.00
7		55b	−0.1	+0.2
7trans (87%)	0.20	63	−0.3	+0.0
7cis (13%)	0.12

^aNMR carried out at 5 °C in pH 6.3 phosphate buffer. Assuming a 0.01 ppm uncertainty in measured Gly H_α/H_α′ separation, error propagation estimates uncertainties of 5% for fraction folded and ~0.2 kcal mol⁻¹ for ΔG_fold and ΔΔG_fold.

^bOverall folded population calculated as product of the fraction of peptide in the trans amide configuration and fraction folded for trans isomer.