Figure 2.

Tryptophan fluorescence spectra of wild-type (A), W441F (B), and W512F (C) HMMs. Conditions were 0.12 mg/ml HMM, 0.45 M KCl, 2 mM MgCl₂, 20 mM Tris⋅HCl (pH 7.5), and 0.5 mM DTT at 25°C with (solid lines) or without (dotted lines) 0.1 mM ATP. Fluorescence spectra in the presence of ATP were recorded 1–3 min after the addition of ATP. Excitation wavelength was 293 nm.