Changes in surface hydrophobicity of purified recombinant full length and N terminus deletion mutants of Pol λ following UV-B irradiation or high salt treatment.

<p>(A) Bis-ANS binding titration of untreated control, UV-B irradiated and high NaCl treated recombinant Pol λ. (B) Bis-ANS binding titration of untreated control, UV-B irradiated and high NaCl treated Del 2 protein. (C) Bis-ANS binding titration of untreated control, UV-B irradiated and high NaCl treated Del 3 protein. (D-F) Representative Scatchard plots of untreated control, UV-B irradiated and high NaCl treated recombinant Pol λ, (G-I) Del 2 protein and (J-L) Del 3 protein for the determination of stoichiometry (<i>n</i>) and the dissociation constant (k_d) respectively. 0.02 mg/mL of each purified protein in 50 mM Tris-HCl buffer, pH 7.5 (containing 1 mM PMSF and 1 mM β-mercaptoethanol) was titrated by addition of aqueous solution of Bis-ANS. The excitation and emission wavelengths were 390 and 490 nm, respectively. The intensities at 490 nm, from the titration, were plotted as a function of Bis-ANS concentration. UV-B and NaCl treatment of purified recombinant proteins were carried out as described under ‘Materials and Methods’.