title: Peptide pinwheels.
abstract: Electrospraying a mixture of Ac-(GA)7K and Ac-A(GA)7K (Ac = acetyl, G = glycine, A = alanine, and K = lysine) peptides produces strong signals for unsolvated dimers and trimers. The conformations of these multimers have been examined with use of ion mobility measurements in conjunction with molecular dynamics simulations. The results suggest that the trimers adopt a pinwheel arrangement of helices with the C-termini tethered together by the protonated lysine side chain from one peptide interacting with the C-terminus of a neighboring helix. This arrangement leads to a cooperative electrostatic stabilization of all the helices through the interaction of the combined charge with the helix dipoles. The dimer adopts a related V-shaped arrangement of helices which is also cooperatively stabilized.
authors.affiliation: Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, USA.
authors.forename: David T
authors.initials: DT
authors.lastname: Kaleta
authors.forename: Martin F
authors.initials: MF
authors.lastname: Jarrold
mesh_terms: D010455:Peptides / Q000737:chemistry*; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D010455:Peptides