title: A setup for simultaneous measurement of infrared spectra and light scattering signals: watching amyloid fibrils grow from intact proteins.
abstract: A setup for the simultaneous measurement of mid-infrared spectra and static light scattering is described that can be used for the analysis of the formation of nanoscale and microscopic aggregates from smaller molecules to biopolymers. It can be easily integrated into sample chambers of infrared spectrometers or combined with laser beams from tunable infrared lasers. Here, its use for the analysis of the formation of amyloid fibrils from intact proteins is demonstrated. The formation of amyloid fibrils or plaques from proteins is a widespread and pathogenetic relevant process, and a number of diseases are caused and correlated with the deposition of amyloid fibrils in cells and tissues. The molecular mechanisms of these transformations, however, are still unclear. We report here the simultaneous measurement of infrared spectra and static light scattering for the analysis of fibril formation from egg-white lysozyme. The transformation of the native form into non-native forms rich in β-sheet structure is measured by analysis of the amide I spectral region in the infrared spectra, which is sensitive for local structures. At the same time, light scattering signals at forward direction as well as the forward/backward ratio, which are sensitive for the number of scattering centers and their approximate sizes, respectively, are collected for the analysis of fibril growth. Thermodynamic and kinetic parameters as well as mechanistic information are deduced from the combination of the two complementary techniques.
authors.affiliation: Institut für Biophysik, Goethe-Universität Frankfurt am Main, Max-von Laue-Straße 1, D-60438 Frankfurt am Main, Germany.
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.affiliation: Institut für Biophysik, Goethe-Universität Frankfurt am Main, Max-von Laue-Straße 1, D-60438 Frankfurt am Main, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Maurer
authors.affiliation: Institut für Biophysik, Goethe-Universität Frankfurt am Main, Max-von Laue-Straße 1, D-60438 Frankfurt am Main, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Roth
authors.affiliation: Institut für Biophysik, Goethe-Universität Frankfurt am Main, Max-von Laue-Straße 1, D-60438 Frankfurt am Main, Germany.
authors.forename: Vitali
authors.initials: V
authors.lastname: Vogel
authors.affiliation: Institut für Biophysik, Goethe-Universität Frankfurt am Main, Max-von Laue-Straße 1, D-60438 Frankfurt am Main, Germany.
authors.forename: Ernst
authors.initials: E
authors.lastname: Winter
authors.affiliation: Institut für Biophysik, Goethe-Universität Frankfurt am Main, Max-von Laue-Straße 1, D-60438 Frankfurt am Main, Germany.
authors.forename: Werner
authors.initials: W
authors.lastname: Mäntele
mesh_terms: D000682:Amyloid / Q000737:chemistry*; D000818:Animals; D002645:Chickens; D008027:Light; D009113:Muramidase / Q000737:chemistry*; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D012542:Scattering, Radiation; D017550:Spectroscopy, Fourier Transform Infrared / Q000295:instrumentation / Q000379:methods
chemical_list: D000682:Amyloid; D009113:Muramidase