Dresden 2011 – scientific programme
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BP: Fachverband Biologische Physik
BP 23: Biopolymers and Biomaterials III (with CPP)
BP 23.8: Talk
Wednesday, March 16, 2011, 17:00–17:15, ZEU 260
Keratin homogeneity in the tail feathers of peacocks — •Silvia Pabisch1,2, Stephan Puchegger1, Ingrid M. Weiss3, Helmut O. Kirchner3, and Herwig Peterlik1 — 1University of Vienna, Faculty of Physics, Vienna, Austria — 2Vienna University of Technology, Institute for Materials Chemistry, Vienna, Austria — 3INM-Leibniz Institute for New Materials, Saarbrücken, Germany
X-ray diffraction studies successfully clarified the structure of avian feathers: Each filament has a helical structure with four repeating units per turn.[1] The structure of avian feathers is very stable though their relative density is low. The keratin structure in the cortex of peacocks' feathers is studied by X-ray diffraction along the feather, from the calamus to the tip. It changes considerably over the first 5 cm close to the calamus and remains constant for about 1 m along the length of the feather. We attribute the X-ray patterns to a shrinkage of a cylindrical arrangement of beta-sheets, which is not fully formed initially. In the final structure, the crystalline beta-cores are fixed by the rest of the keratin molecule. The hydrophobic residues of the beta core are locked into a zip-like arrangement. Tensile and compression tests are additionally performed in-situ to follow the structural change as consequence of varying load.
[1] R.D.B. Fraser and D.A.D. Perry, J. Struct. Biol. 162 (2008) 1-13.