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| | ==Crystal Structure of the E.coli SeqA protein complexed with N6-methyladenine- guanine mismatch DNA== | | ==Crystal Structure of the E.coli SeqA protein complexed with N6-methyladenine- guanine mismatch DNA== |
| - | <StructureSection load='1j3e' size='340' side='right' caption='[[1j3e]], [[Resolution|resolution]] 2.50Å' scene=''> | + | <StructureSection load='1j3e' size='340' side='right'caption='[[1j3e]], [[Resolution|resolution]] 2.50Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[1j3e]] is a 3 chain structure with sequence from [http://en.wikipedia.org/wiki/"bacillus_coli"_migula_1895 "bacillus coli" migula 1895]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1J3E OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1J3E FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[1j3e]] is a 3 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1J3E OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1J3E FirstGlance]. <br> |
| - | </td></tr><tr id='NonStdRes'><td class="sblockLbl"><b>[[Non-Standard_Residue|NonStd Res:]]</b></td><td class="sblockDat"><scene name='pdbligand=6MA:N6-METHYL-DEOXY-ADENOSINE-5-MONOPHOSPHATE'>6MA</scene></td></tr> | + | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.5Å</td></tr> |
| - | <tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[1iu3|1iu3]]</td></tr> | + | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=6MA:N6-METHYL-DEOXY-ADENOSINE-5-MONOPHOSPHATE'>6MA</scene></td></tr> |
| - | <tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">SeqA ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=562 "Bacillus coli" Migula 1895])</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=1j3e FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1j3e OCA], [https://pdbe.org/1j3e PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1j3e RCSB], [https://www.ebi.ac.uk/pdbsum/1j3e PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1j3e ProSAT], [https://www.topsan.org/Proteins/RSGI/1j3e TOPSAN]</span></td></tr> |
| - | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1j3e FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1j3e OCA], [http://pdbe.org/1j3e PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1j3e RCSB], [http://www.ebi.ac.uk/pdbsum/1j3e PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=1j3e ProSAT], [http://www.topsan.org/Proteins/RSGI/1j3e TOPSAN]</span></td></tr> | + | |
| | </table> | | </table> |
| | == Function == | | == Function == |
| - | [[http://www.uniprot.org/uniprot/SEQA_ECOLI SEQA_ECOLI]] Negative regulator of replication initiation, which contributes to regulation of DNA replication and ensures that replication initiation occurs exactly once per chromosome per cell cycle. Binds to pairs of hemimethylated GATC sequences in the oriC region, thus preventing assembly of replication proteins and re-initiation at newly replicated origins. Repression is relieved when the region becomes fully methylated. Can also bind to hemimethylated GATC sequences outside of oriC region. Binds, with less affinity, to fully methylated GATC sites and affects timing of replication. May play a role in chromosome organization and gene regulation.<ref>PMID:8011018</ref> <ref>PMID:7891562</ref> <ref>PMID:7553853</ref> <ref>PMID:11080170</ref> <ref>PMID:10931282</ref> <ref>PMID:20689753</ref> | + | [https://www.uniprot.org/uniprot/SEQA_ECOLI SEQA_ECOLI] Negative regulator of replication initiation, which contributes to regulation of DNA replication and ensures that replication initiation occurs exactly once per chromosome per cell cycle. Binds to pairs of hemimethylated GATC sequences in the oriC region, thus preventing assembly of replication proteins and re-initiation at newly replicated origins. Repression is relieved when the region becomes fully methylated. Can also bind to hemimethylated GATC sequences outside of oriC region. Binds, with less affinity, to fully methylated GATC sites and affects timing of replication. May play a role in chromosome organization and gene regulation.<ref>PMID:8011018</ref> <ref>PMID:7891562</ref> <ref>PMID:7553853</ref> <ref>PMID:11080170</ref> <ref>PMID:10931282</ref> <ref>PMID:20689753</ref> |
| | == Evolutionary Conservation == | | == Evolutionary Conservation == |
| | [[Image:Consurf_key_small.gif|200px|right]] | | [[Image:Consurf_key_small.gif|200px|right]] |
| | Check<jmol> | | Check<jmol> |
| | <jmolCheckbox> | | <jmolCheckbox> |
| - | <scriptWhenChecked>select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/j3/1j3e_consurf.spt"</scriptWhenChecked> | + | <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/j3/1j3e_consurf.spt"</scriptWhenChecked> |
| | <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked> | | <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked> |
| | <text>to colour the structure by Evolutionary Conservation</text> | | <text>to colour the structure by Evolutionary Conservation</text> |
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| | __TOC__ | | __TOC__ |
| | </StructureSection> | | </StructureSection> |
| - | [[Category: Bacillus coli migula 1895]] | + | [[Category: Escherichia coli]] |
| - | [[Category: Fujikawa, N]] | + | [[Category: Large Structures]] |
| - | [[Category: Hiraga, S]] | + | [[Category: Fujikawa N]] |
| - | [[Category: Kurumizaka, H]] | + | [[Category: Hiraga S]] |
| - | [[Category: Nureki, O]] | + | [[Category: Kurumizaka H]] |
| - | [[Category: Structural genomic]]
| + | [[Category: Nureki O]] |
| - | [[Category: Tanaka, Y]] | + | [[Category: Tanaka Y]] |
| - | [[Category: Yamazoe, M]] | + | [[Category: Yamazoe M]] |
| - | [[Category: Yokoyama, S]] | + | [[Category: Yokoyama S]] |
| - | [[Category: Mismatched dna]]
| + | |
| - | [[Category: Protein-dna complex]]
| + | |
| - | [[Category: Recognition of hemimethylated dna]]
| + | |
| - | [[Category: Replication]]
| + | |
| - | [[Category: Replication-dna complex]]
| + | |
| - | [[Category: Rsgi]]
| + | |
| Structural highlights
Function
SEQA_ECOLI Negative regulator of replication initiation, which contributes to regulation of DNA replication and ensures that replication initiation occurs exactly once per chromosome per cell cycle. Binds to pairs of hemimethylated GATC sequences in the oriC region, thus preventing assembly of replication proteins and re-initiation at newly replicated origins. Repression is relieved when the region becomes fully methylated. Can also bind to hemimethylated GATC sequences outside of oriC region. Binds, with less affinity, to fully methylated GATC sites and affects timing of replication. May play a role in chromosome organization and gene regulation.[1] [2] [3] [4] [5] [6]
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 Escherichia coli SeqA protein recognizes the 11 hemimethylated G-mA-T-C sites in the oriC region of the chromosome, and prevents replication over-initiation within one cell cycle. The crystal structure of the SeqA C-terminal domain with hemimethylated DNA revealed the N6-methyladenine recognition mechanism; however, the mechanism of discrimination between the hemimethylated and fully methylated states has remained elusive. In the present study, we performed mutational analyses of hemimethylated G-mA-T-C sequences with the minimal DNA-binding domain of SeqA (SeqA71-181), and found that SeqA71-181 specifically binds to hemimethylated DNA containing a sequence with a mismatched mA:G base pair [G-mA(:G)-T-C] as efficiently as the normal hemimethylated G-mA(:T)-T-C sequence. We determined the crystal structures of SeqA71-181 complexed with the mismatched and normal hemimethylated DNAs at 2.5 and 3.0 A resolutions, respectively, and found that the mismatched mA:G base pair and the normal mA:T base pair are recognized by SeqA in a similar manner. Furthermore, in both crystal structures, an electron density is present near the unmethylated adenine, which is only methylated in the fully methylated state. This electron density, which may be due to a water molecule or a metal ion, can exist in the hemimethylated state, but not in the fully methylated state, because of steric clash with the additional methyl group.
Structural and biochemical analyses of hemimethylated DNA binding by the SeqA protein.,Fujikawa N, Kurumizaka H, Nureki O, Tanaka Y, Yamazoe M, Hiraga S, Yokoyama S Nucleic Acids Res. 2004 Jan 2;32(1):82-92. Print 2004. PMID:14704346[7]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Lu M, Campbell JL, Boye E, Kleckner N. SeqA: a negative modulator of replication initiation in E. coli. Cell. 1994 May 6;77(3):413-26. PMID:8011018
- ↑ von Freiesleben U, Rasmussen KV, Schaechter M. SeqA limits DnaA activity in replication from oriC in Escherichia coli. Mol Microbiol. 1994 Nov;14(4):763-72. PMID:7891562
- ↑ Slater S, Wold S, Lu M, Boye E, Skarstad K, Kleckner N. E. coli SeqA protein binds oriC in two different methyl-modulated reactions appropriate to its roles in DNA replication initiation and origin sequestration. Cell. 1995 Sep 22;82(6):927-36. PMID:7553853
- ↑ Brendler T, Sawitzke J, Sergueev K, Austin S. A case for sliding SeqA tracts at anchored replication forks during Escherichia coli chromosome replication and segregation. EMBO J. 2000 Nov 15;19(22):6249-58. PMID:11080170 doi:10.1093/emboj/19.22.6249
- ↑ Skarstad K, Lueder G, Lurz R, Speck C, Messer W. The Escherichia coli SeqA protein binds specifically and co-operatively to two sites in hemimethylated and fully methylated oriC. Mol Microbiol. 2000 Jun;36(6):1319-26. PMID:10931282
- ↑ Sanchez-Romero MA, Busby SJ, Dyer NP, Ott S, Millard AD, Grainger DC. Dynamic distribution of seqa protein across the chromosome of escherichia coli K-12. MBio. 2010 May 18;1(1). pii: e00012-10. doi: 10.1128/mBio.00012-10. PMID:20689753 doi:10.1128/mBio.00012-10
- ↑ Fujikawa N, Kurumizaka H, Nureki O, Tanaka Y, Yamazoe M, Hiraga S, Yokoyama S. Structural and biochemical analyses of hemimethylated DNA binding by the SeqA protein. Nucleic Acids Res. 2004 Jan 2;32(1):82-92. Print 2004. PMID:14704346 doi:http://dx.doi.org/10.1093/nar/gkh173
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