View source for 1q57

[[Image:1q57.jpg|left|200px]]

 {{Structure
|PDB= 1q57 |SIZE=350|CAPTION= <scene name='initialview01'>1q57</scene>, resolution 3.45&Aring;
|SITE= 
|LIGAND= 
|ACTIVITY= 
|GENE= 4 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=10760 Enterobacteria phage T7])
|DOMAIN=
|RELATEDENTRY=[[1e0j|1E0J]], [[1cr0|1CR0]], [[1nui|1NUI]], [[1e0k|1E0K]], [[1cr1|1CR1]], [[1cr2|1CR2]], [[1cr4|1CR4]]
|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1q57 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1q57 OCA], [http://www.ebi.ac.uk/pdbsum/1q57 PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1q57 RCSB]</span>
}}

'''The Crystal Structure of the Bifunctional Primase-Helicase of Bacteriophage T7'''


==Overview==
Within minutes after infecting Escherichia coli, bacteriophage T7 synthesizes many copies of its genomic DNA. The lynchpin of the T7 replication system is a bifunctional primase-helicase that unwinds duplex DNA at the replication fork while initiating the synthesis of Okazaki fragments on the lagging strand. We have determined a 3.45 A crystal structure of the T7 primase-helicase that shows an articulated arrangement of the primase and helicase sites. The crystallized primase-helicase is a heptamer with a crown-like shape, reflecting an intimate packing of helicase domains into a ring that is topped with loosely arrayed primase domains. This heptameric isoform can accommodate double-stranded DNA in its central channel, which nicely explains its recently described DNA remodeling activity. The double-jointed structure of the primase-helicase permits a free range of motion for the primase and helicase domains that suggests how the continuous unwinding of DNA at the replication fork can be periodically coupled to Okazaki fragment synthesis.

==About this Structure==
1Q57 is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Enterobacteria_phage_t7 Enterobacteria phage t7]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1Q57 OCA]. 

==Reference==
The crystal structure of the bifunctional primase-helicase of bacteriophage T7., Toth EA, Li Y, Sawaya MR, Cheng Y, Ellenberger T, Mol Cell. 2003 Nov;12(5):1113-23. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/14636571 14636571]
[[Category: Enterobacteria phage t7]]
[[Category: Single protein]]
[[Category: Cheng, Y.]]
[[Category: Ellenberger, T.]]
[[Category: Li, Y.]]
[[Category: Sawaya, M R.]]
[[Category: Toth, E A.]]
[[Category: dna replication]]
[[Category: dntpase]]
[[Category: helicase]]
[[Category: primase]]

''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 30 23:08:59 2008''