| Popis: |
Protein aggregation is a complex, multistep process, but the first step is likely the formation of a dimer through non-specific interactions of two disordered monomers. In this work we measure the rate of reconfiguration, or intramolecular diffusion, of monomeric Abeta peptides and find a correlation between this rate and the aggregation rate. Using the method of Trp-Cys contact quenching we find that the rate of reconfiguration is ∼5 times faster for Abeta40, which aggregates slowly, than for Abeta42, which aggregates quickly. Furthermore, the rate of reconfiguration for Abeta42 speeds up at higher pH, which slows aggregation, and in the presence of the aggregation inhibitor curcumin. These results are commensurate with a model of the first step of aggregation, described here, that is a kinetic competition between reconfiguration and bimolecular diffusion. |
