title: Crystal structure of a thermostable type B DNA polymerase from Thermococcus gorgonarius.
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.
authors: Abteilung Strukturforschung, Max-Planck-Institut für Biochemie, D-82152 Martinsried, Germany. hopfner@scripps.edu
authors: K P
authors: KP
authors: Hopfner
authors: A
authors: A
authors: Eichinger
authors: R A
authors: RA
authors: Engh
authors: F
authors: F
authors: Laue
authors: W
authors: W
authors: Ankenbauer
authors: R
authors: R
authors: Huber
authors: B
authors: B
authors: Angerer
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D003001:Cloning, Molecular; D003196:Computer Graphics; D017124:Conserved Sequence; D018360:Crystallography, X-Ray / Q000379:methods; D004256:DNA Polymerase I / Q000737:chemistry* / Q000378:metabolism; D004795:Enzyme Stability; D006358:Hot Temperature; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D019712:Thermococcus / Q000201:enzymology*; D013816:Thermodynamics
chemical_list: D011994:Recombinant Proteins; D004256:DNA Polymerase I