Structural alignment of T7 and Taq DNA polymerases.
Atomic coordinates of the crystal structures of Taq DNA
polymerase (38) (PDB entry 2KTQ) and T7 DNA polymerase (35) (PDB entry
1T7P) were superimposed by using the program insight ii
(Biosym Technologies, San Diego). The superimposed structures were
visualized by using the program setor (41). T7 DNA
polymerase (light grey) bound to the thioredoxin molecule (orange),
primer (purple), and the template (cyan) are shown. The different
domains of the T7 DNA polymerase are indicated. Only the I and I1
helices of Taq DNA polymerase (dark grey) are shown
here, superimposed on the corresponding helices of T7 DNA polymerase.
The loop unique to T7 DNA polymerase, comprising residues
Glu-Gly-Asp-Lys spanning from residue 401 through 404, is shown in
green.