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. Author manuscript; available in PMC: 2012 Jul 1.
Published in final edited form as: Biophys Chem. 2011 Jan 22;156(2-3):115–127. doi: 10.1016/j.bpc.2011.01.006

Figure 10.

Figure 10

Schematic model of the pol β-ssDNA complex formation. In the initial complex, the enzyme engages only the 8-kDa domain in a process accompanied by the release of the large number, ~16 – 19, water molecules and characterized by zero or a small positive ΔHo. The entire potential DNA binding subsite of the 8-kDa domain is involved in interactions with the nucleic acid. Transition to the (pol β)5 binding mode includes reorientation of the 8 -kDa domain with respect to the 31-kDa domain. The process is accompanied by the net uptake of ~ 10 water molecules by the 8-kDa domain and a large positive ΔHo. The final engagement of the total DNA-binding site in forming the (pol β)16 binding mode, involves engagement of the DNA -binding subsite on the 31-kDa domain in interactions with the nucleic acid, without additional water release and accompanied by a small negative ΔHo (details in text).