Polar side chains drive the association of model transmembrane peptides

摘要: The forces stabilizing the three-dimensional structures of membrane proteins are currently not well understood. Previously, it was shown that a single Asn side chain in transmembrane segment can mediate dimerization and trimerization variety hydrophobic helices. Here, we examine tendencies representative set amino acids (Asn, Gln, Asp, Glu, Lys, Ala, Val, Leu, Ser, Thr) to direct oligomerization model helix. peptide is entirely throughout 20-residue contains central site for introduction various acid “guests.” Analytical ultracentrifugation gel electrophoresis were used determine stoichiometry free energy association entire peptides within micelles. Variants with two polar atoms at guest site—Asn, Glu—formed stable trimers, whereas residues one or fewer showed much weaker tendency associate. data examined light frequencies occurrence chains provide insight into role interactions directing helix association. These also suggest an approach design variants natural single-span potentials associate bilayer.