The effect of helix-breaking residues on Poly(LA)7

Abstract

The purpose of this project is to study the effect of helix-breaking residues on a single pass transmembrane ?-helical peptide, Poly(LA)7 in aqueous and lipid environments. This was achieved by creating four substitutions containging either Glycine or Proline: the mutated peptides contained single or double substitution. VMD software was used to set up MD simulations in water and DLPG membrane. RMSF and analysis of [phi] and [psi] dihedral angles were employed to evaluate the extent of the distortion caused by the introduction of the helix-breaking-resdiues into an [alpha]-helical peptide. Double substitutions lead to more significant conformational changes and partial unfolding of Poly(LA)7 peptides. Longer simulation times will help to further study the effect of Glycine and Proline on transmembrane helical peptides.