Circular Dichroism Study of Late Embryogenesis Abundant Peptides in Reverse Micelles

Abstract

Late Embryogenesis Abundant (LEA) proteins are a class of characteristically unstructured proteins found within plants at their later stages of seed development. While LEA proteins lack distinct structural characteristics under standard conditions, certain extreme conditions of temperature or drought may allow the formation of functional structure. Through the use of Circular Dichroism (CD) spectroscopy, the structural characteristics of two different 11-mer repeat units of Group 3 LEA proteins has been studied. Here, solutions of the peptides in AOT reverse micelles have been used to simulate conditions of low peptide hydration, with a variety of w0 values investigated. In comparison to aqueous CD results which confirm the characteristic disordered structure of LEA proteins, CD results in reverse micelles suggest a preference for α-helical character under low hydration conditions. Furthermore, temperature-dependent CD scans show interesting non-monotonic behavior. These results enhance our understanding of how LEA proteins may be structured biologically and allow further speculation regarding their role in seed development.