Abstract
Group-3 late embryogenesis abundant (G3LEA) proteins are expressed in anhydrobiotic organisms experiencing desiccation stress and their major segments consist of repeated and conserved 11-mer amino acid units. However, little information has been obtained with regard to the properties of these repeat units. Here, we performed replica exchange molecular dynamics (REMD) simulations for a short model peptide in which the 11-mer motif is repeated two times. And for comparison the similar simulation was performed for a control peptide without such sequence regularity. It was found that the LEA model peptide has a high propensity to form the α-helical coiled coil structure in vacuo, while such a tendency was not observed for the control peptide. These results are consistent with our previous FTIR results for the corresponding peptides in the dry state. At the global energy minimum, two LEA peptide chains were shown to form right-handed coiled coil with an antiparallel arrangement, and to come in contact with each other through the interaction of hydrophilic residues. In conclusion, the intermolecular electrostatic interactions are the main driving force of the above coiled coil formation.
