Conformational analysis of the secalin storage proteins of rye (Secale cereale L.)

Cd spectroscopy of purified groups of secalins at room temperature and in cryogenic solvent systems demonstrated that the ω-, HMW and 40k γ-secalins have conformations similar to the homologous groups of prolamins present in barley and wheat. In particular, the proline-rich repetitive sequences present in the ω- and 40k γ-secalins appear to undergo temperature-dependent transitions between conformations rich in poly-L-proline II structure (at low temperature) and β-turns (at room temperature). These structures are the dominant types in the ω-secalins, but are combined with α-helical structures (present in non-repetitive domain) in the 40k ysecalins. The presence of more extensive repeats in the 75k γ-secalins results in spectral characteristics more like those of w-secalins.