view article

Figure 8
(a) ITC titration of Hyp-1 with ANS. The top panel shows raw heat data for 54 consecutive injections of 5 mM ANS into the sample cell (200 µl) containing 0.145 mM Hyp-1 in 25 mM HEPES pH 7.4 at 298 K. The bottom panel shows the binding isotherm created by plotting the heat peak areas against the molar ratio of ANS added to the protein. The line represents the best fit to the model of N independent sites. ANS binding is endothermic with 1:3 stoichiometry (N = 3.14 ± 0.02) and a Kd of 108 ± 3 µM. The change in enthalpy ΔH is −7213 ± 77 cal mol−1 and that in entropy ΔS is −6.04 cal mol−1 K−1. (b) ANS binding to Hyp-1 monitored fluorometrically by titration of 1 µM ANS in 25 mM HEPES pH 7.4 with Hyp-1. The line represents the best fit to the equation F = Fmax[protein]/(Kd + [protein]). The calculated Kd value is 58 ± 4 µM (R2 of fitting 0.9878).

Journal logoSTRUCTURAL
ISSN: 2059-7983
Follow Acta Cryst. D
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds