PDBsum entry: 1cmw

Transferase

PDB id: 1cmw

Contents

Protein chain

817 a.a. *

* Residue conservation analysis

Obsolete entry

PDB id:

1cmw

Name:

Transferase

Title:

Crystal structure of taq DNA-polymerase shows a new orientation for the structure-specific nuclease domain

Structure:

Protein (DNA polymerase i). Chain: a. Engineered: yes

Source:

Thermus aquaticus. Organism_taxid: 271. Expressed in: escherichia coli. Expression_system_taxid: 562. Expression_system_cell_line: bl21

Resolution:

2.60Å R-factor: 0.192 R-free: 0.245

Authors:

U.K.Urs,R.Murali,H.M.K.Murthy

Key ref:

U.K.Urs et al. (1999). Structure of taq DNA polymerase shows a new orientation for the structure-specific nuclease domain. Acta Crystallogr D Biol Crystallogr, 55, 1971-1977. PubMed id: 10666572 DOI: 10.1107/S090744499901135X

Date:

11-May-99 Release date: 15-Jan-00

Protein chain

P19821  (DPO1_THEAQ) -  DNA polymerase I, thermostable

Seq: 832 a.a.

Struc: 817 a.a.

Enzyme reactions

• Enzyme class: E.C.2.7.7.7 - DNA-directed Dna polymerase.
• Reaction: Deoxynucleoside triphosphate + DNA(n) = diphosphate + DNA(n+1)

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

reference

DOI no: 10.1107/S090744499901135X

Acta Crystallogr D Biol Crystallogr 55:1971-1977 (1999)

PubMed id: 10666572

Structure of taq DNA polymerase shows a new orientation for the structure-specific nuclease domain.

U.K.Urs, R.Murali, H.M.Krishna Murthy.

ABSTRACT

Thermus aquaticus DNA polymerase I consists of the polymerase, the structure-specific nuclease and the vestigial editing nuclease domains. Three-dimensional structures of the native enzyme and its complex with DNA have already been reported. The structure of a complex with an inhibitory antibody has also been determined. The structure of the native enzyme in a different crystal form determined at 2.6 A is reported here. Optimized anomalous diffraction measurements made at the holmium L(III) edge were valuable in validating solutions obtained through molecular replacement. The structure of the polymerase domain is similar to those reported previously, while the relative orientation of the structure-specific nuclease domain is significantly different from those of the native enzyme and the DNA complex; it is, however, identical to that observed in the structure of the Fab complex. In the structures of the native enzyme and of the DNA complex reported previously, the active site of the structure-specific nuclease domain is too far from that of the polymerase domain, making it difficult to propose a structural model for the in vivo primer-excision and nick-translation activities of the enzyme. In the present structure, the two active sites are considerably closer. Taken together, the reported structure of the native enzyme, that of the Fab complex and the present structure imply that the different orientation of the structure-specific nuclease domain is probably a consequence of intrinsically high relative mobility between these two domains in this enzyme.