Self-Assembly of a Model Peptide Incorporating a Hexa-HistidineSequence Attached to an Oligo-Alanine Sequence, and Binding to GoldNTA/Nickel Nanoparticles.

Amyloid fibrils are formed by a modelsurfactant-like peptide (Ala)10-(His)6containinga hexa-histidine tag. Thispeptide undergoes a remarkable two-step self-assembly process withtwo distinct critical aggregation concentrations (cac’s), probedby fluorescence techniques. A micromolar range cac is ascribed tothe formation of prefibrillar structures, whereas a millimolar rangecac is associated with the formation of well-defined but more compactfibrils. We examine the labeling of these model tagged amyloid fibrilsusing Ni-NTA functionalized gold nanoparticles (Nanogold). Successfullabeling is demonstrated via electron microscopy imaging. The specificityof tagging does not disrupt the β-sheet structure of the peptidefibrils. Binding of fibrils and Nanogold is found to influence thecircular dichroism associated with the gold nanoparticle plasmon absorptionband. These results highlight a new approach to the fabrication offunctionalized amyloid fibrils and the creation of peptide/nanoparticlehybrid materials. [ABSTRACT FROM AUTHOR]