Figure 4. Ca²⁺-free sNUCB1 inhibits hIAPP amyloidogenesis in a state-independent manner.

hIAPP (32 µM) aggregation was monitored using thio-T (32 µM). The lag phase is shown in blue, the growth phase in green and the stationary phase in yellow. Aggregation was allowed to proceed to (A) the nucleation phase at 7 min, (B) the mid-point of growth phase at 15 min and (C) the initiation of stationary phase at 40 min. At the indicated time, samples were removed and an equimolar amount (32 µM) of Ca²⁺-free sNUCB1 was added. The pink circles indicate the time points at which sNUCB1 was added. TEM images were collected immediately before addition of sNUCB1 and 60 min after addition of sNUCB1. The micrographs corresponding to samples withdrawn at 60 min after addition show that Ca²⁺-free sNUCB1 both effectively inhibits the progression of seeds into mature fibrils and disaggregates mature fibrils. Scale bars represent 200 nm.