title: Crystal structures of the Klenow fragment of DNA polymerase I complexed with deoxynucleoside triphosphate and pyrophosphate.
abstract: Crystal structures of the Klenow fragment (KF) of DNA polymerase I from Escherichia coli complexed with deoxynucleoside triphosphate (dNTP) or with pyrophosphate (PPi) determined to 3.9-A resolution by X-ray crystallography show these molecules binding within the cleft of the polymerase domain and surrounded by residues previously implicated in dNTP binding. The dNTP binds adjacent to the O-helix [Ollis, D. L., Brick, P., Hamlin, R., Xuong, N. G., & Steitz, T. A. (1985a) Nature 313, 762-766] with its triphosphate moiety anchored by three positively charged residues, Arg 754, Arg 682, and Lys 758, plus His 734 and Gln 708. The dNTP binding site observed in the crystal is consistent with the results of chemical modification including cross-linking and is also near many of the amino acid residues whose mutation affects catalysis [Polesky, A. H., Steitz, T. A., Grindley, N. D. F., & Joyce, C. M. (1990) J. Biol. Chem. 265, 14579-14591; Polesky, A. H., Dahlberg, M. E., Benkovic, S. J., Grindley, N. D. F., & Joyce, C. M. (1992) J. Biol. Chem. 267, 8417-8428]. However, we conclude that the position of at least the dNMP moiety of dNTP in the binary complex is not likely to be the same as in its catalytically relevant complex with primer-template DNA.
authors.affiliation: Department of Molecular Biophysics, Yale University, New Haven, Connecticut 06511.
authors.forename: L S
authors.initials: LS
authors.lastname: Beese
authors.forename: J M
authors.initials: JM
authors.lastname: Friedman
authors.forename: T A
authors.initials: TA
authors.lastname: Steitz
mesh_terms: D001665:Binding Sites; D018360:Crystallography, X-Ray; D004256:DNA Polymerase I / Q000737:chemistry*; D003854:Deoxyribonucleotides / Q000737:chemistry; D011756:Diphosphates / Q000737:chemistry; D005092:Exonucleases / Q000737:chemistry; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D017434:Protein Structure, Tertiary; D013329:Structure-Activity Relationship
chemical_list: D003854:Deoxyribonucleotides; D011756:Diphosphates; D004256:DNA Polymerase I; D005092:Exonucleases