Presentación

Monolayer Sensitivity Enables a 2D IR Spectroscopic Immuno-biosensor for Studying Protein Structures: Application to Amyloid Polymorphs

“…27,28 Transient oligomers are difficult to study because they exist at low concentrations, are in equilibrium with monomers, and are kinetically evolving toward fibrils. 29 By creating an immunosensor using antibodies that are selective for hIAPP, we extract a subset of the protein populations and record their 2D IR spectrum. We establish a new approach for studying protein structures with 2D IR spectroscopy and discover, through measurements of proteins with a single amino acid isotopically labeled, that these particular antibodies selectively trap specific amyloid polymorphs.…”

“…27,28,36,37 The antibodies are broad spectrum, which can bind both fibrils and oligomers, so we used solutions with fibrils prepared according to our previous studies. 29,38,39 We aggregated 1 mM hIAPP, synthesized according to previously published methods, 32,40 in buffer overnight to create amyloid fibrils. Amyloid fibrils are extremely stable species, and so under these conditions very small amounts of monomers and oligomers would be expected.…”

“…These experiments validate the use of high-concentration studies for studying oligomer structure. 29 We previously published data proposing an aggregation mechanism in which all fibrillar polymorphs originate from the same oligomer structure. 38 The data presented here support this hypothesis, because we see no polymorphs when the antibodies are incubated with hIAPP during the lag time, prior to fibril formation when only oligomers are present.…”