Structural highlights
Function
[DPOL_BPPH2] This polymerase possesses two enzymatic activities: DNA synthesis (polymerase) and an exonucleolytic activity that degrades single-stranded DNA in the 3'- to 5'-direction. [TERM_BPPH2] DNA terminal protein is linked to the 5'-ends of both strands of the genome through a phosphodiester bond between the beta-hydroxyl group of a serine residue and the 5'-phosphate of the terminal deoxyadenylate. This protein is essential for DNA replication and is involved in the priming of DNA elongation. May act as an exolysin that hydrolyzes peptidoglycans during virus entry into the host cell.
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
The absolute requirement for primers in the initiation of DNA synthesis poses a problem for replicating the ends of linear chromosomes. The DNA polymerase of bacteriophage phi29 solves this problem by using a serine hydroxyl of terminal protein to prime replication. The 3.0 A resolution structure shows one domain of terminal protein making no interactions, a second binding the polymerase and a third domain containing the priming serine occupying the same binding cleft in the polymerase as duplex DNA does during elongation. Thus, the progressively elongating DNA duplex product must displace this priming domain. Further, this heterodimer of polymerase and terminal protein cannot accommodate upstream template DNA, thereby explaining its specificity for initiating DNA synthesis only at the ends of the bacteriophage genome. We propose a model for the transition from the initiation to the elongation phases in which the priming domain of terminal protein moves out of the active site as polymerase elongates the primer strand. The model indicates that terminal protein should dissociate from polymerase after the incorporation of approximately six nucleotides.
The phi29 DNA polymerase:protein-primer structure suggests a model for the initiation to elongation transition.,Kamtekar S, Berman AJ, Wang J, Lazaro JM, de Vega M, Blanco L, Salas M, Steitz TA EMBO J. 2006 Mar 22;25(6):1335-43. Epub 2006 Mar 2. PMID:16511564[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Kamtekar S, Berman AJ, Wang J, Lazaro JM, de Vega M, Blanco L, Salas M, Steitz TA. The phi29 DNA polymerase:protein-primer structure suggests a model for the initiation to elongation transition. EMBO J. 2006 Mar 22;25(6):1335-43. Epub 2006 Mar 2. PMID:16511564
