Effect of ATP on the chaperone activity of <i>M</i>. <i>leprae</i> HSP18.

<p><b>(A)</b> DTT-induced aggregation of 0.05 mg/ml lysozyme (Lys) in the absence and presence 0.05 mg/ml HSP18 preincubated with 0.01–3 mM ATP at 25°C. Aggregation was initiated by adding 20 mM DTT and scattering at 400 nm was monitored at 37°C. Trace 1: Lys alone; Trace 2: Lys + 0.01 mM ATP; Trace 3: Lys + 0.05 mM ATP; Trace 4: Lys + 0.2 mM ATP;Trace 5: Lys + 0.5 mM ATP;Trace 6: Lys + 1 mM ATP; Trace 7: Lys + 2 mM ATP;Trace 8: Lys + 3 mM ATP; Trace 9:Lys + HSP18; Trace 10: Lys + HSP18 preincubated with 0.01 mM ATP; Trace 11: Lys + HSP18 preincubated with 0.05 mM ATP; Trace 12: Lys + HSP18 preincubated with 0.2 mM ATP; Trace 13: Lys + HSP18 preincubated with 0.5 mM ATP; Trace 14: Lys + HSP18 preincubated with 1 mM ATP; Trace 15: Lys + HSP18 preincubated with 2 mM ATP; and Trace 16: Lys + HSP18 preincubated with 3 mM ATP; <b>(B)</b> Percent protection ability of <i>M</i>. <i>leprae</i> HSP18 against lysozyme aggregation in the absence and presence of 0.01–3.0 mM ATP at 37°C. Data are means ± the standard deviation from triplicate determinations; <b>(C)</b> Thermal aggregation of CS (0.06 mg/ml) at 43°C. Prior to this measurement, HSP18 was preincubated with or without 0.01/1 mM ATP for 1 hr at 25°C. Trace 1: CS alone; Trace 2: CS + 0.01 mM ATP; Trace 3: CS + 1 mM ATP; Trace 4: CS + HSP18; Trace 5: CS + HSP18 preincuabted with 0.01 mM ATP; Trace 6: CS + HSP18 preincuabted with 1 mM ATP; <b>(D)</b> Percent protection ability of <i>M</i>. <i>leprae</i> HSP18 against CS aggregation in the absence and presence of 0.01/1 mM ATP at 43°C. Data are means ± the standard deviation from triplicate determinations.*<i>p</i>< 0.05, **<i>p</i>< 0.005 and ***<i>p</i>< 0.0005.</p>