title: Assembly of triple-stranded beta-sheet peptides at interfaces.
abstract: A 30-residue peptide, BS30, which incorporates two proline residues to induce reverse turns, was designed to form a triple-stranded beta-sheet monolayer at the air-water interface. To discern the structural role of proline, a second peptide, BS30G, identical to BS30 but with glycine residues replacing proline, was prepared and examined in parallel fashion. Surface pressure-molecular area isotherms indicated a limiting area per molecule (ca. 460 A(2)) for BS30 that corresponds well to that estimated from the known dimensions of crystalline beta-sheet monolayers (492 A(2)). Comparable measurements on BS30G yielded a smaller molecular area (380 A(2)). Grazing incidence X-ray diffraction measurements performed on the BS30 monolayer at nominal area per molecule of 500 A(2), exhibited two Bragg peaks corresponding to 4.79 and 34.9 A spacings, consistent with formation of triple-stranded beta-sheet structures that assemble into two-dimensional crystallites at the air-water interface. Visualized by Brewster angle microscopy, BS30 monolayers displayed uniform, solidlike domains, whereas BS30G appeared to be disordered.
authors.affiliation: Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena 91125, USA.
authors.forename: Hanna
authors.initials: H
authors.lastname: Rapaport
authors.forename: Gunter
authors.initials: G
authors.lastname: Möller
authors.forename: Charles M
authors.initials: CM
authors.lastname: Knobler
authors.forename: Torben R
authors.initials: TR
authors.lastname: Jensen
authors.forename: Kristian
authors.initials: K
authors.lastname: Kjaer
authors.forename: Leslie
authors.initials: L
authors.lastname: Leiserowitz
authors.forename: David A
authors.initials: DA
authors.lastname: Tirrell
mesh_terms: D010455:Peptides / Q000737:chemistry*; D011487:Protein Conformation; D014961:X-Ray Diffraction
chemical_list: D010455:Peptides