4r7y: Difference between revisions
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The | ==Crystal structure of an active MCM hexamer== | ||
<StructureSection load='4r7y' size='340' side='right'caption='[[4r7y]], [[Resolution|resolution]] 2.70Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[4r7y]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Pyrococcus_furiosus_DSM_3638 Pyrococcus furiosus DSM 3638] and [https://en.wikipedia.org/wiki/Saccharolobus_solfataricus_P2 Saccharolobus solfataricus P2]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4R7Y OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4R7Y 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]] 2.7Å</td></tr> | |||
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ADP:ADENOSINE-5-DIPHOSPHATE'>ADP</scene>, <scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene></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=4r7y FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4r7y OCA], [https://pdbe.org/4r7y PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4r7y RCSB], [https://www.ebi.ac.uk/pdbsum/4r7y PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4r7y ProSAT]</span></td></tr> | |||
</table> | |||
== Function == | |||
[https://www.uniprot.org/uniprot/Q8U3I4_PYRFU Q8U3I4_PYRFU] [https://www.uniprot.org/uniprot/MCM_SACS2 MCM_SACS2] Presumptive replicative helicase. Has ATPase and DNA helicase activities. The latter preferentially melts 5'-tailed oligonucleotides and is stimulated by the SSB protein (single-stranded DNA binding protein). The active ATPase sites in the MCM ring are formed through the interaction surfaces of two neighboring subunits such that a critical structure of a conserved arginine finger motif is provided in trans relative to the ATP-binding site of the Walker A box of the adjacent subunit. The helicase function is proposed to use a partially sequential mode of ATP hydrolysis; the complex appears to tolerate multiple catalytically inactive subunits.<ref>PMID:11821426</ref> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
In a previous Research article (<xref>Froelich et al., 2014</xref>), we suggested an MCM helicase activation mechanism, but were limited in discussing the ATPase domain because it was absent from the crystal structure. Here we present the crystal structure of a nearly full-length MCM hexamer that is helicase-active and thus has all features essential for unwinding DNA. The structure is a chimera of Sulfolobus solfataricus N-terminal domain and Pyrococcus furiosus ATPase domain. We discuss three major findings: 1) a novel conformation for the A-subdomain that could play a role in MCM regulation; 2) interaction of a universally conserved glutamine in the N-terminal Allosteric Communication Loop with the AAA+ domain helix-2-insert (h2i); and 3) a recessed binding pocket for the MCM ssDNA-binding motif influenced by the h2i. We suggest that during helicase activation, the h2i clamps down on the leading strand to facilitate strand retention and regulate ATP hydrolysis. | |||
Analysis of the crystal structure of an active MCM hexamer.,Miller JM, Arachea BT, Epling LB, Enemark EJ Elife. 2014 Sep 29;3. doi: 10.7554/eLife.03433. PMID:25262915<ref>PMID:25262915</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
<div class="pdbe-citations 4r7y" style="background-color:#fffaf0;"></div> | |||
== References == | |||
<references/> | |||
__TOC__ | |||
</StructureSection> | |||
[[Category: Large Structures]] | |||
[[Category: Pyrococcus furiosus DSM 3638]] | |||
[[Category: Saccharolobus solfataricus P2]] | |||
[[Category: Arachea BT]] | |||
[[Category: Enemark EJ]] | |||
[[Category: Epling LB]] | |||
[[Category: Miller JM]] | |||
