γ-Zein secondary structure in solution by circular dichroism

• Published in: Biopolymers Vol. 89; no. 3; pp. 175 - 178
• Main Authors: Bicudo, Tatiana C., Bicudo, Rogério C., Forato, Lucimara A., Beltramini, Leila M., Batista, Luiz A. R., Filho, Rubens Bernardes, Colnago, Luiz A.
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01-03-2008
• Subjects: Amino Acid Motifs; circular dichroism; Circular Dichroism - methods; Dithiothreitol - chemistry; maize prolamin; Nuclear Magnetic Resonance, Biomolecular - methods; Peptides - chemistry; polyproline II helix; Proline; protein secondary structure; Protein Structure, Secondary; Protein Structure, Tertiary; Sodium Dodecyl Sulfate - chemistry; Solutions - chemistry; Spectroscopy, Fourier Transform Infrared - methods; Zea mays - chemistry; Zea mays - classification; Zein - chemistry; Zein - isolation & purification; γ-zein
• ISSN: 0006-3525; 1097-0282
• DOI: 10.1002/bip.20884

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.
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