FIGURE 1.

X-ray crystal binary (PDB entry 1XSL, green) and ternary (PDB entry 1XSN, red) pol λ/DNA complexes. (a) Superimposed C_α trace of x-ray crystal binary and ternary pol-λ complexes. Differences between the x-ray crystal structures in the thumb and palm subdomains are shown by the arrows. (b) Position of the DNA template strand and templating base at the gap in the x-ray crystal binary and ternary structures of pol λ. The incoming nucleotide (dTTP) and active-site residues Asp⁴²⁷, Asp⁴²⁹, and Asp⁴⁹⁰ of the ternary x-ray crystal structure are also shown. Key distances between the crystal binary and ternary states are provided and hydrogens are omitted from the DNA for clarity.