title: Electrostatic control of thickness and stiffness in a designed protein fiber.
abstract: Attempts to design peptide-based fibers from first principles test our understanding of protein folding and assembly, and potentially provide routes to new biomaterials. Several groups have presented such designs based on alpha-helical and beta-strand building blocks. A key issue is this area now is engineering and controlling fiber morphology and related properties. Previously, we have reported the design and characterization of a self-assembling peptide fiber (SAF) system based on alpha-helical coiled-coil building blocks. With preceding designs, the SAFs are thickened, highly ordered structures in which many coiled coils are tightly bundled. As a result, the fibers behave as rigid rods. Here we report successful attempts to design new fibers that are thinner and more flexible by further programming at the amino-acid sequence level. This was done by introducing extended, or "smeared", electrostatic networks of arginine and glutamate residues to the surfaces of the coiled-coil building blocks. Furthermore, using arginine--rather than lysine--in these networks plays a major role in the fiber assembly, presumably by facilitating multidentate intra and intercoiled-coil salt bridges.
authors: School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK..
authors: David
authors: D
authors: Papapostolou
authors: Elizabeth H C
authors: EH
authors: Bromley
authors: Christopher
authors: C
authors: Bano
authors: Derek N
authors: DN
authors: Woolfson
mesh_terms: D000595:Amino Acid Sequence; D002942:Circular Dichroism; D046529:Microscopy, Electron, Transmission; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry; D011506:Proteins / Q000737:chemistry* / Q000648:ultrastructure; D012996:Solutions; D017550:Spectroscopy, Fourier Transform Infrared; D055672:Static Electricity; D014461:Ultracentrifugation
chemical_list: D010455:Peptides; D011506:Proteins; D012996:Solutions