Figure 6.

Conformational exchange experienced by Pol β. Residues displaying elevated R₂ and ¹⁵N-CPMG relaxation dispersion curves are shown as blue and red spheres, respectively, corresponding to Cα atoms. (a) The apo form shows millisecond dynamics predominantly in the lyase domain (residues 1–90). Residues with k_ex ~1400 s⁻¹ are shown as smaller spheres while residues with k_ex ~4000 s⁻¹ are shown as larger red spheres. Few residues in the other polymerase domains show elevated R2 values; (b) Onlyresidue Glu21 displays ¹⁵N-CPMG relaxation dispersion in the binary form. Other residues displaying elevated R2 values are located in the polymerase domain of Pol β. DNA in the binary form is shown in black. The relaxation data used for preparing this figure were taken from reference [8].