γ‐Zein secondary structure in solution by circular dichroism

Abstract

Abstract The proline‐rich N‐terminal domain of γ‐zein has been reported in relevant processes, which include its ability to cross the cell membranes. Evidences indicate that synthetic hexapeptide (PPPVHL), naturally found in N‐terminal portion of γ‐zein, can adopt the polyproline II (PPII) conformation in aqueous solution. The secondary structure of γ‐zein in maize protein bodies had been analyzed by solid state Fourier transform infrared and nuclear magnetic resonance spectroscopies. However, it was not possible to measure PPII content in physiological environment since the β‐sheet and PPII signals overlap in both solid state techniques. Here, the secondary structure of γ‐zein has been analyzed by circular dichroism in SDS aqueous solution with and without ditiothreitol (DTT), and in 60% of 2‐propanol and water with DTT. The results show that γ‐zein has high helical content in all solutions. The PPII conformation was present at about 7% only in water/DTT solution. © 2007 Wiley Periodicals, Inc. Biopolymers 89: 175–178, 2008. This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley. com