Vibrational Sensing in Super-Resolution Two-Dimensional Infrared Imaging

University Of Delaware, Newark DE

Investigators

Abstract

Project Summary Vibrational Sensing in Super-Resolution Two-Dimensional Infrared Imaging Many amyloidogenic peptides are implicated in diseases ranging from Alzheimer’s to diabetes to cardiomyopathy. Chaperone proteins such as HSP27 and αB-crystallin serve a protective role by interacting with amyloidogenic peptides to protect against amyloid diseases. However, amyloidogenic peptides such as desmin fragments are susceptible to polymorphism, when the same peptide forms different amyloid secondary structures, and it is not fully understood how this impacts the binding of chaperone proteins. We hypothesize that chaperone proteins may interact with these amyloid polymorphs differently. Gaining a fundamental understanding of chaperone-peptide interactions would lead to better targeted design strategies for chaperone-fragment based drugs. However, we need a better tool set to understand the fundamentals of chaperone-peptide interactions. Two-dimensional infrared (2DIR) imaging has the potential to transform what we know about amyloidogenic peptide-chaperone interactions by revealing secondary structural detail of a heterogeneous peptide and protein population. 2DIR is an ultrafast vibrational spectroscopy technique sensitive to protein secondary structural changes and isotope labeling. Here, our goal is to better understand how chaperones interact with amyloidogenic peptides and measure their changes in secondary structure using improved 2DIR microscopy. In Aim 1, we will improve 2DIR microscopy spatially and temporally to create the first ever super-resolution 2DIR microscope. These innovations will result in the first ever super-resolution 2DIR microscope. Aim 2 will focus on bulk 2DIR measurements utilizing vibrational sensing of isotope labeling to understand important peptide-chaperone contacts. 13C18O backbone labeling will isolate regions or individual amino acids of peptides, and 13C segmental growth will isolate domains of chaperone proteins. Our model system will investigate how chaperone proteins HSP27 and αB-crystallin affect desmin peptide fragment aggregation in cardiomyopathy. We will also measure how domains of HSP27 and αB-crystallin change structure during preventative contacts with desmin via isotope labeling for vibrational sensing. This project will be the first to combine an isotope labeling approach with 2DIR imaging to better understand peptide aggregation. This project will provide the first kinetic 2DIR data ever distinguishing aggregating amyloid peptides from an added chaperone. Importantly, we can apply our 2DIR bioimaging and isotope labeling strategies in collaboration with Research Project 3 of this COBRE for IR- active modes of boron clusters and Research Project 4 for amyloid β-fibril investigations. Ultimately, this Research Project will result in an entirely new bioimaging tool that can be applied to many future biophysical protein questions.