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[[Image:1q57.jpg|left|200px]]<br /><applet load="1q57" size="350" color="white" frame="true" align="right" spinBox="true"
caption="1q57, resolution 3.45&Aring;" />
'''The Crystal Structure of the Bifunctional Primase-Helicase of Bacteriophage T7'''<br />


==Overview==
==The Crystal Structure of the Bifunctional Primase-Helicase of Bacteriophage T7==
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.
<StructureSection load='1q57' size='340' side='right'caption='[[1q57]], [[Resolution|resolution]] 3.45&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1q57]] is a 7 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_phage_T7 Escherichia phage T7]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1Q57 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1Q57 FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 3.45&#8491;</td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1q57 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1q57 OCA], [https://pdbe.org/1q57 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1q57 RCSB], [https://www.ebi.ac.uk/pdbsum/1q57 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1q57 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/HELIC_BPT7 HELIC_BPT7] ATP-dependent DNA helicase and primase essential for viral DNA replication and recombination (PubMed:21606333, PubMed:22977246, PubMed:32009150). The helicase moves 5' -> 3' on the lagging strand template, unwinding the DNA duplex ahead of the leading strand polymerase at the replication fork and generating ssDNA for both leading and lagging strand synthesis (PubMed:21606333, PubMed:22977246, PubMed:32009150). ATP or dTTP hydrolysis propels each helicase domain to translocate 2 nt per step sequentially along DNA (PubMed:30679383, PubMed:17604719). Mediates strand transfer when a joint molecule is available and participates in recombinational DNA repair through its role in strand exchange (PubMed:9096333, PubMed:8617248). Primase activity synthesizes short RNA primers at the sequence 5'-GTC-3' on the lagging strand that the polymerase elongates using dNTPs and providing the primase is still present (PubMed:6454135, PubMed:9139692).[HAMAP-Rule:MF_04154]<ref>PMID:17604719</ref> <ref>PMID:21606333</ref> <ref>PMID:22977246</ref> <ref>PMID:30679383</ref> <ref>PMID:32009150</ref> <ref>PMID:6454135</ref> <ref>PMID:8617248</ref> <ref>PMID:9096333</ref> <ref>PMID:9139692</ref>
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/q5/1q57_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=1q57 ConSurf].
<div style="clear:both"></div>


==About this Structure==
==See Also==
1Q57 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacteriophage_t7 Bacteriophage t7]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1Q57 OCA].
*[[RNA polymerase 3D structures|RNA polymerase 3D structures]]
 
== References ==
==Reference==
<references/>
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://ispc.weizmann.ac.il//pmbin/getpm?pmid=14636571 14636571]
__TOC__
[[Category: Bacteriophage t7]]
</StructureSection>
[[Category: Single protein]]
[[Category: Escherichia phage T7]]
[[Category: Cheng, Y.]]
[[Category: Large Structures]]
[[Category: Ellenberger, T.]]
[[Category: Cheng Y]]
[[Category: Li, Y.]]
[[Category: Ellenberger T]]
[[Category: Sawaya, M R.]]
[[Category: Li Y]]
[[Category: Toth, E A.]]
[[Category: Sawaya MR]]
[[Category: dna replication]]
[[Category: Toth EA]]
[[Category: dntpase]]
[[Category: helicase]]
[[Category: primase]]
 
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:35:57 2008''

Latest revision as of 11:13, 14 February 2024

The Crystal Structure of the Bifunctional Primase-Helicase of Bacteriophage T7The Crystal Structure of the Bifunctional Primase-Helicase of Bacteriophage T7

Structural highlights

1q57 is a 7 chain structure with sequence from Escherichia phage T7. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 3.45Å
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

HELIC_BPT7 ATP-dependent DNA helicase and primase essential for viral DNA replication and recombination (PubMed:21606333, PubMed:22977246, PubMed:32009150). The helicase moves 5' -> 3' on the lagging strand template, unwinding the DNA duplex ahead of the leading strand polymerase at the replication fork and generating ssDNA for both leading and lagging strand synthesis (PubMed:21606333, PubMed:22977246, PubMed:32009150). ATP or dTTP hydrolysis propels each helicase domain to translocate 2 nt per step sequentially along DNA (PubMed:30679383, PubMed:17604719). Mediates strand transfer when a joint molecule is available and participates in recombinational DNA repair through its role in strand exchange (PubMed:9096333, PubMed:8617248). Primase activity synthesizes short RNA primers at the sequence 5'-GTC-3' on the lagging strand that the polymerase elongates using dNTPs and providing the primase is still present (PubMed:6454135, PubMed:9139692).[HAMAP-Rule:MF_04154][1] [2] [3] [4] [5] [6] [7] [8] [9]

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

See Also

References

  1. ↑ Johnson DS, Bai L, Smith BY, Patel SS, Wang MD. Single-molecule studies reveal dynamics of DNA unwinding by the ring-shaped T7 helicase. Cell. 2007 Jun 29;129(7):1299-309. PMID:17604719 doi:10.1016/j.cell.2007.04.038
  2. ↑ Zhang H, Lee SJ, Zhu B, Tran NQ, Tabor S, Richardson CC. Helicase-DNA polymerase interaction is critical to initiate leading-strand DNA synthesis. Proc Natl Acad Sci U S A. 2011 Jun 7;108(23):9372-7. doi:, 10.1073/pnas.1106678108. Epub 2011 May 23. PMID:21606333 doi:http://dx.doi.org/10.1073/pnas.1106678108
  3. ↑ Kulczyk AW, Akabayov B, Lee SJ, Bostina M, Berkowitz SA, Richardson CC. An interaction between DNA polymerase and helicase is essential for the high processivity of the bacteriophage T7 replisome. J Biol Chem. 2012 Nov 9;287(46):39050-60. doi: 10.1074/jbc.M112.410647. Epub 2012, Sep 12. PMID:22977246 doi:http://dx.doi.org/10.1074/jbc.M112.410647
  4. ↑ Gao Y, Cui Y, Fox T, Lin S, Wang H, de Val N, Zhou ZH, Yang W. Structures and operating principles of the replisome. Science. 2019 Feb 22;363(6429). pii: science.aav7003. doi:, 10.1126/science.aav7003. Epub 2019 Jan 24. PMID:30679383 doi:http://dx.doi.org/10.1126/science.aav7003
  5. ↑ Ma JB, Chen Z, Xu CH, Huang XY, Jia Q, Zou ZY, Mi CY, Ma DF, Lu Y, Zhang HD, Li M. Dynamic structural insights into the molecular mechanism of DNA unwinding by the bacteriophage T7 helicase. Nucleic Acids Res. 2020 Apr 6;48(6):3156-3164. PMID:32009150 doi:10.1093/nar/gkaa057
  6. ↑ Tabor S, Richardson CC. Template recognition sequence for RNA primer synthesis by gene 4 protein of bacteriophage T7. Proc Natl Acad Sci U S A. 1981 Jan;78(1):205-9. PMID:6454135 doi:10.1073/pnas.78.1.205
  7. ↑ Kong D, Richardson CC. Single-stranded DNA binding protein and DNA helicase of bacteriophage T7 mediate homologous DNA strand exchange. EMBO J. 1996 Apr 15;15(8):2010-9 PMID:8617248
  8. ↑ Kong D, Griffith JD, Richardson CC. Gene 4 helicase of bacteriophage T7 mediates strand transfer through pyrimidine dimers, mismatches, and nonhomologous regions. Proc Natl Acad Sci U S A. 1997 Apr 1;94(7):2987-92. PMID:9096333
  9. ↑ Kusakabe T, Richardson CC. Gene 4 DNA primase of bacteriophage T7 mediates the annealing and extension of ribo-oligonucleotides at primase recognition sites. J Biol Chem. 1997 May 9;272(19):12446-53. PMID:9139692 doi:10.1074/jbc.272.19.12446

1q57, resolution 3.45Å

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