Singular value decomposition analysis of the secondary structure features contributing to the circular dichroism spectra of model proteins

ABSTRACT: Amyloid fibril formation occurs in restricted environment, such as the interface between intercellular fluids and bio-membranes. Conformational interconversion from α-helix to β-structure does not progress in fluids; however, it can occur after sedimentary aggregation during amyloid fibril formation induced by heat treatment of hen egg white lysozyme (HEWL). Secondary structures of various proteins and denatured proteins titrated with 2,2,2-trifluoroethanol (TFE) were examined using their CD spectra. Gaussian peak/trough and singular value decompositions (SVD) showed that the spectral pattern of the α-helix comprised a sharp trough at wavelength 207 nm and a broad trough at 220 nm. Conversely, we distinguished two patterns for β-sheet—a spread barrel type, corresponding to ConA, and a tightly weaved type, corresponding to the soybean trypsin inhibitor. Herein, we confirmed that the spectral/conformational interconversion of the heat-treated HEWL was not observed in the dissolved fluid. Highlights • The application of singular value decomposition (SVD) of the CD spectrum to secondary protein structure analysis is a useful method.• We distinguished two patterns for β-sheet—a spread barrel type and a tightly weaved type.• We confirmed that the spectral/conformational interconversion of the heat-treated HEWL was not observed in the dissolved fluid.

SUBMITTER: Shiratori T 

PROVIDER: S-EPMC8528683 | biostudies-literature |

REPOSITORIES: biostudies-literature