Circular dichroism and absorption of the polytetrapeptide of elastin: A polymer model for the β-turn

Abstract

Circular dichroism and absorption data are reported for the polytetrapeptide of elastin, HCO-(Val-Pro-Gly-Gly)40-Val-OMe. The circular dichroism pattern, with a negative band at 224 nm, a positive band at 205 nm and a second negative band below 190 nm, is distinct from the circular dichroism patterns exhibited by the α-helix, β-pleated sheet and random coil conformations. As previous nuclear magnetic resonance studies have demonstrated that the polytetrapeptide is comprised of repeating β-turns, the absorption and circular dichroism data is presented as a model system for the β-turn conformational feature which is commonly found in globular proteins. The absorption and circular dichroism data are resolved into component Gaussian curves.