posted on 2021-08-26, 07:12authored bySidney
S. Dicke, Ariel M. Alperstein, Kathryn L. Schueler, Donald S. Stapleton, Shane P. Simonett, Caitlyn R. Fields, Farzaneh Chalyavi, Mark P. Keller, Alan D. Attie, Martin T. Zanni
We used two-dimensional IR bioimaging
to study the structural heterogeneity
of formalin-fixed mouse pancreas. Images were generated from the hyperspectral
data sets by plotting quantities associated with the amide I vibrational
mode, which is created by the backbone carbonyl stretch. Images that
measure the fundamental vibrational frequencies, cross peaks, and
anharmonic shifts are presented. Histograms are generated for each
quantity, providing averaged values and distributions around the mean
that serve as metrics for protein structures. Images were generated
from tissue that had been stored in a formalin fixation for 3, 8,
and 48 weeks. Over this period, all three metrics show that that the
β-sheet content of the samples increased, consistent with protein
aggregation. Our results indicate that formalin fixation does not
entirely arrest the degradation of a protein structure in pancreas
tissue.