Secondary Structural Preferences of Some Antibacterial Cyclooctapeptides in the Presence of Calcium(II)

Figure 4

CD spectra of COP 7–9 in (a) 100 mM Ca²⁺ only, (b) in 10 mM DPC only, and (c) in 10 mM DPC following titrations with Ca²⁺ at a Ca²⁺/COP ratio of 60.

(a)

(b)

(c)