Observation of [beta]-sheet aggregation in a gas-phase tau-peptide dimer

Infrared (IR)/ultraviolet (UV) hole-burning spectroscopy is used for examining the aggregation of the protected segment (Ac-VQIVYK-NHMe) in the NH stretch region in a cold molecular beam in order to characterize its structure and identify the noncovalent interactions responsible for aggregation and stabilization in amyloid peptides. The studies have shown that the tau-protein fragments form extended [beta]-strands that are combined in a [beta]-sheet through characteristic backbone hydrogen bonds, indicating that this secondary structure is very energetic and is readily formed in the gas phase.