Table 1.

Circular dichroism data

Peptide	Cassette designationa	[Θ]222nm (benign)b	[Θ]222nm (50% TFE)b	[Θ]222/208 nm (benign)c	[Θ]222/208 nm (50% TFE)c	% Helixd
1	•••	−28,700	−31,100	1.05	0.96	92.3
2	••○	−28,400	−30,000	1.01	0.92	94.7
3	○••	−33,100	−32,100	1.03	0.93	103.1
4	•○•	−26,900	−29,600	1.01	0.94	90.9
5	•○○	−29,000	−32,300	1.02	0.94	89.8
6	○•○	−35,400	−34,600	1.05	0.92	102.3
7	○○•	−28,300	−32,500	1.00	0.93	87.0
8	○○○	−28,200	−32,600	1.00	0.92	86.5

^a Sequences are shown in Figure 2 ▶. Filled circles denote Ile or Leu and open circles denote Ala in the a and d positions of the cassette shown in Figure 2 ▶.

^b Calculated from the following formula: [Θ] = Θ_obs × MRW / [10 × path length (cm) × concentration (mg/mL)] where MRW is the mean residue weight (molecular mass of the peptide divided by the number of helical residues). Benign refers to 50 mM potassium phosphate buffer, 0.1 M KCl (pH 7.0), and TFE is trifluoroethanol.

^c [Θ]_{222/208 nm} is the ratio of the [Θ]₂₂₂ divided by the [Θ]_208nm.

^d % Helix is calculated from the molar ellipticity at 222 nm divided by the molar ellipticity in 50% TFE times 100. The value in 50% TFE represents the maximum α-helical content and is taken as 100%.