1xi1
From Proteopedia
Phi29 DNA polymerase ssDNA complex, monoclinic crystal form
Overview
The DNA polymerase from phage phi29 is a B family polymerase that initiates replication using a protein as a primer, attaching the first nucleotide of the phage genome to the hydroxyl of a specific serine of the priming protein. The crystal structure of phi29 DNA polymerase determined at 2.2 A resolution provides explanations for its extraordinary processivity and strand displacement activities. Homology modeling suggests that downstream template DNA passes through a tunnel prior to entering the polymerase active site. This tunnel is too small to accommodate double-stranded DNA and requires the separation of template and nontemplate strands. Members of the B family of DNA polymerases that use protein primers contain two sequence insertions: one forms a domain not previously observed in polymerases, while the second resembles the specificity loop of T7 RNA polymerase. The high processivity of phi29 DNA polymerase may be explained by its topological encirclement of both the downstream template and the upstream duplex DNA.
About this Structure
1XI1 is a Single protein structure of sequence from Bacillus phage phi29. Full crystallographic information is available from OCA.
Reference
Insights into strand displacement and processivity from the crystal structure of the protein-primed DNA polymerase of bacteriophage phi29., Kamtekar S, Berman AJ, Wang J, Lazaro JM, de Vega M, Blanco L, Salas M, Steitz TA, Mol Cell. 2004 Nov 19;16(4):609-18. PMID:15546620 Page seeded by OCA on Sat May 3 15:03:33 2008
