Fig. 4.

Conformational change in H2 fibrils by pH jump. a pH 2.9 fibrils (left) reversibly changed to pH 7.5-like fibrils (middle), in which two conformations were separated by a relatively low energy barrier, by shifting the solution pH from 2.9 to 7.5. However, pH 7.5-like fibrils did not change to pH 7.5 fibrils (right), in which these two conformations were separated by a high energy barrier. b, c Circular dichroism spectra (b) and Fourier transform infrared spectra (c) exhibited the secondary structural changes of pH 2.9 fibrils depending on the solution pH