CD spectra of Porin molecules?
CD (circular dichroism) spectrum of porin will look like CD spectra of most beta-sheet-reach proteins. You can look, for example, paper on PorB protein (Minetti et al, JBC, 1998) where authors present CD spectra of one of porines:

Circular dichroism spectra of recombinant PorB class 3 protein as a function of SDS. Standard solutions of PorB rclass 3 protein (1.0 mg/ml) dialyzed against a buffer comprised of 10 mM sodium phosphate and 0.05% zwittergent 3-14 and incubated with varying concentrations of SDS (0-1%) at 25.0 °C for 24 h prior to spectroscopic analysis. Far UV CD spectra are recorded for rclass 3 in the absence of SDS (solid circles) and at the following SDS concentrations: 0.15% (open triangles), 0.25% (solid squares), 0.30% (open diamonds), 0.40% (solid triangles), 0.45% (open circles), 0.50% (solid diamonds), and 1.0% (open squares).