1em8

<StructureSection load='1em8' size='340' side='right' caption='[[1em8]], [[Resolution|resolution]] 2.10&Aring;' scene=''>

<table><tr><td colspan='2'>[[1em8]] is a 4 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=1EM8 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1EM8 FirstGlance]. <br>

</td></tr><tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/DNA-directed_DNA_polymerase DNA-directed DNA polymerase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.7.7 2.7.7.7] </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=1em8 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1em8 OCA], [http://pdbe.org/1em8 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1em8 RCSB], [http://www.ebi.ac.uk/pdbsum/1em8 PDBsum]</span></td></tr>

[[http://www.uniprot.org/uniprot/HOLC_ECOLI HOLC_ECOLI]] DNA polymerase III is a complex, multichain enzyme responsible for most of the replicative synthesis in bacteria. This DNA polymerase also exhibits 3' to 5' exonuclease activity. [[http://www.uniprot.org/uniprot/HOLD_ECOLI HOLD_ECOLI]] DNA polymerase III is a complex, multichain enzyme responsible for most of the replicative synthesis in bacteria. This DNA polymerase also exhibits 3' to 5' exonuclease activity. The exact function of the psi subunit is unknown.

<scriptWhenChecked>select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/em/1em8_consurf.spt"</scriptWhenChecked>

</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/chain_selection.php?pdb_ID=2ata ConSurf].

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== Publication Abstract from PubMed ==

The chi (chi) and psi (psi) subunits of Escherichia coli DNA polymerase III form a heterodimer that is associated with the ATP-dependent clamp-loader machinery. In E. coli, the chi:psi heterodimer serves as a bridge between the clamp-loader complex and the single-stranded DNA-binding protein. We determined the crystal structure of the chi:psi heterodimer at 2.1 A resolution. Although neither chi (147 residues) nor psi (137 residues) bind to nucleotides, the fold of each protein is similar to the folds of mononucleotide-(chi) or dinucleotide-(psi) binding proteins, without marked similarity to the structures of the clamp-loader subunits. Genes encoding chi and psi proteins are found to be readily identifiable in several bacterial genomes and sequence alignments showed that residues at the chi:psi interface are highly conserved in both proteins, suggesting that the heterodimeric interaction is of functional significance. The conservation of surface-exposed residues is restricted to the interfacial region and to just two other regions in the chi:psi complex. One of the conserved regions was found to be located on chi, distal to the psi interaction region, and we identified this as the binding site for a C-terminal segment of the single-stranded DNA-binding protein. The other region of sequence conservation is localized to an N-terminal segment of psi (26 residues) that is disordered in the crystal structure. We speculate that psi is linked to the clamp-loader complex by this flexible, but conserved, N-terminal segment, and that the chi:psi unit is linked to the single-stranded DNA-binding protein via the distal surface of chi. The base of the clamp-loader complex has an open C-shaped structure, and the shape of the chi:psi complex is suggestive of a loose docking within the crevice formed by the open faces of the delta and delta' subunits of the clamp-loader.

Crystal structure of the chi:psi sub-assembly of the Escherichia coli DNA polymerase clamp-loader complex.,Gulbis JM, Kazmirski SL, Finkelstein J, Kelman Z, O'Donnell M, Kuriyan J Eur J Biochem. 2004 Jan;271(2):439-49. PMID:14717711<ref>PMID:14717711</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

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<div class="pdbe-citations 1em8" style="background-color:#fffaf0;"></div>

*[[DNA polymerase|DNA polymerase]]

[[Category: Bacillus coli migula 1895]]

[[Category: DNA-directed DNA polymerase]]

[[Category: Donnell, M O]]

[[Category: Finkelstein, J]]

[[Category: Gulbis, J M]]

[[Category: Kuriyan, J]]

[[Category: Alpha-beta fold]]

[[Category: Heterodimer]]