Fig. 6.

Chaperone-like activity of DmHsp22WT and its arginine mutants by using luciferase (Luc) (a, b) and insulin (c, d) as protein substrates. The heat and DTT-induced aggregation of Luc and insulin were assayed using absorbance at 320 nm for Luc assay and 340 nm for DTT-induced insulin aggregation assay at different temperatures (42 °C for Luc and 37 °C for DTT-induced aggregation of insulin). a, b Heat-induced aggregation of Luc (0.1 μM) was measured for 30 min in HEPES-KOH 50 mM (pH, 7.5) to make the molar ratio of 0.5:1 for sHsp to substrate. c, d DTT-induced aggregation of insulin (52 μM) in 10 mM potassium phosphate buffer (pH, 7.9) containing 100 mM NaCl was measured in absence or presence of DmHsp22WT or arginine mutants (7.57 μM). The final molar ratio of sHsps to insulin is 1:7. These results are representative of three independent experiments