Structural studies of the Klentaq1 DNA polymerase

DNA polymerase I enzymes have served as model systems to study the mechanis m of template-directed DNA polymerization. This process requires that the e nzyme cycles through a series of conformational changes, each cycle leading to the incorporation of a nucleotide to the primer strand of the DNA. The kinetics of nucleotide incorporation has been extensively studied leading t o the definition of specific steps along the cycle. Efforts to visualize th ese steps using X-ray crystallography have recently come to fruition, notab ly for one particular DNA polymerase I system, that of Klentaql. This revie w focuses on the structural characterization of the various steps along the nucleotide incorporation pathway.