Abstract

We are interested in the self-assembly of de novo designed or naturally occurring peptide sequences into amyloid fibrils; this includes variants of the TTR105 -115 peptide and the chaplins from the bacteria Streptomycetes coelicolor.

In this talk I will describe how we have used synthetic DNA molecules, known as DNA origami, to nucleate and organize the growth of amyloid fibrils. A 20 -helix DNA nanotube was used to sheathe amyloid fibrils and to organize the fibrils onto predefined two-dimensional platforms via DNA –DNA hybridization interactions.

Other materials have been created from a family of peptide variants based on the TTR105 -115 sequence and we are seeking to better understand how mammalian cells interact with these designed fibrils. We have tracked the interactions of these fibrils with cells and separated the effects of the topographic physical and chemical structural features on cell behavior.

The five chaplin peptides produced by Streptomycetes coelicolor provide an interesting contrast, as these peptides are surface active and assemble both in solution and at the air-water interface. We have found surprising differences in the properties and assembly of the individual chaplin peptides that potentially allow control of the self-assembly process. Molecular dynamics simulations have also provided new insights into intermediate structures that may determine the rates of assembly in these pathways.