In Alzheimer's disease, β-amyloid peptides (βA1–40 and βA1–42) are deposited on the brain cell surfaces as neurotoxic plaques. Some reports indicate that small heat shock proteins, Hsp27 and αB-crystallin, colocalize in the plaques, but their functions are not known. Interaction between βA and αB-crystallin must be determined in order to understand the role of αB-crystallin in βA fibril formation. We used a pyrene (Pyr)-labeled βA1–40 in a fluorescence energy transfer experiment. Upon incubation together at 37°C, energy transfer between Trp of αB-crystallin and Pyr of Pyr-labeled βA was observed, indicating that βA participated in subunit exchange of αB-crystallin, which promoted fibril formation.
