VUVCD spectra of metMb (a), SNase (b), and Trx (c) in various conformational states: N (solid black line), H (red line), C (blue line), A (green line), PA (brown line), and U (dotted black line). Inset shows the temperature dependence of the molar ellipticity at 192, 190, and 196 nm for metMb, SNase, and Trx, respectively. The experimental conditions are detailed in the Materials and Methods.