PMID: 10097083 , Related PDB id: 1TGO

Authors:

Hopfner KP, Eichinger A, Engh RA, Laue F, Ankenbauer W, Huber R, Angerer B

Title:

Crystal structure of a thermostable type B DNA polymerase from Thermococcus gorgonarius.

Journal:

Proc Natl Acad Sci U S A. 1999 Mar 30;96(7):3600-5.

Abstract:

Most known archaeal DNA polymerases belong to the type B family, which also includes the DNA replication polymerases of eukaryotes, but maintain high fidelity at extreme conditions. We describe here the 2.5 A resolution crystal structure of a DNA polymerase from the Archaea Thermococcus gorgonarius and identify structural features of the fold and the active site that are likely responsible for its thermostable function. Comparison with the mesophilic B type DNA polymerase gp43 of the bacteriophage RB69 highlights thermophilic adaptations, which include the presence of two disulfide bonds and an enhanced electrostatic complementarity at the DNA-protein interface. In contrast to gp43, several loops in the exonuclease and thumb domains are more closely packed; this apparently blocks primer binding to the exonuclease active site. A physiological role of this "closed" conformation is unknown but may represent a polymerase mode, in contrast to an editing mode with an open exonuclease site. This archaeal B DNA polymerase structure provides a starting point for structure-based design of polymerases or ligands with applications in biotechnology and the development of antiviral or anticancer agents.