External stresses cause certain proteins to lose their regular structure and aggregate. In order to clarify this abnormal
aggregation process, a structural evolution of human recombinant aB-crystallin under UV irradiation was observed
with in situ small-angle neutron scattering. The abnormal aggregation process was identified to fall in three time
zones: incubation, aggregation, and saturation. During the incubation time, the size of aggregates was almost
unchanged but a deformation in the local structure was developing. After the incubation time, abnormal aggregation
proceed. When the volume of the aggregates reached around twice the size as that of the initial aggregates, the
aggregation rate slowed down, which marked the onset of saturation.