RELATING THE BULK STRUCTURE OF AMYLOID TO THE
CONSTITUENT FIBRILS AND THEIR INTERACTIONS
Salman S Rogers and Athene M Donald
Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE
We are studying the structure and mechanical properties of -lactoglobulin
amyloid solutions and gels on macro- and microscopic length scales to
understand the interfibrillar interactions better and how they lead to the bulk gel
structure. We have measured the decay of the flow birefringence in the fibrillar
solution with time, which is related to the rotational diffusion constant of the
rods, and have found that the viscosity decays under high shear rate, due to the
break up of fibrils or aggregates of fibrils. We plan to use neutron scattering to
study the interfibrillar interactions via their excluded volume. These methods,
which do not destroy the solution conditions, can be related to TEM results on
the fibril structure. Several models may account for the bulk gel structure: a
glass of semi-flexible rods, random association or cross-links by weak forces in
solution, or even branching growth.