Characterization of the boundary zone of a cast protein drop: fibroin beta-sheet and nanofibril formation.
We have studied a cast fibroin drop with grazing incidence small-angle X-ray scattering, imaging, and spectroscopy techniques. Optical microscopy shows that the dried drop forms a boundary zone. Grazing-incidence small-angle X-ray scattering performed with a synchrotron radiation microbeam in the boundary zone suggests the formation of nanometer-sized domains with one-dimensional paracrystalline order. Atomic force microscopy and scanning electron microscopy support a nanofibrillar morphology. MicroRaman spectroscopy shows the formation of beta-sheet secondary structure in the boundary zone, which is attributed to a shearing effect due to the retraction of the drop boundary upon evaporation.
European Synchrotron Radiation Facility, B.P. 220, F-38043 Grenoble Cedex, France.
Ronald
R
Gebhardt
Charlotte
C
Vendrely
Manfred
M
Burghammer
Christian
C
Riekel
D000818:Animals; D005349:Fibroins / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D049329:Nanostructures / Q000737:chemistry*; D017433:Protein Structure, Secondary; D013059:Spectrum Analysis, Raman; D013499:Surface Properties
D005349:Fibroins