The formation of insoluble amyloid fibrils from native-state proteins is linked to diseases such as Alzheimer's disease (AD) and type-Ⅱ diabetes. Amyloid deposits develop when proteins misfold out of their native conformations and aggregate into insoluble fibrils, characterized by a cross-β motif in which β-strands run orthogonal to the fibril axis and repetitive hydrogen bonding extends parallel to the axis. This cross-β structure may be the global minimum energy conformation for a wide variety of proteins, and identifying this structural motif in small model peptide systems and characterizing it under different conditions can yield valuable clues about its stability, both in general and in specific systems, and about the molecular-level details of amyloid formation. In this communication, we characterize an amyloidogenic peptide dimer in the isolated environment of a cold molecular beam using IR spectroscopy and density functional theory (DFT) calculations. These first results suggest the formation of a β-sheet conformation and highly motivate further analysis of this interesting system.
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