View source for 6kc0


==fused To-MtbCsm1 with 2ATP==
<StructureSection load='6kc0' size='340' side='right'caption='[[6kc0]], [[Resolution|resolution]] 2.29&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6KC0 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6KC0 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]] 2.295&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ATP:ADENOSINE-5-TRIPHOSPHATE'>ATP</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</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=6kc0 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6kc0 OCA], [https://pdbe.org/6kc0 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6kc0 RCSB], [https://www.ebi.ac.uk/pdbsum/6kc0 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6kc0 ProSAT]</span></td></tr>
</table>
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== Publication Abstract from PubMed ==
Prokaryotic CRISPR/Cas systems confer immunity against invading nucleic acids through effector complexes. Csm1, the signature protein of Type III effector complexes, catalyses cyclic oligoadenylate synthesis when in the effector complex, but not when alone, activating the Csm6 nuclease and switching on the antiviral response. Here, we provide biochemical evidence that M. tuberculosis Csm1 (MtbCsm1) has ion-dependent polymerase activity when independent of the effector complex. Structural studies provide supporting evidence that the catalytic core of the MtbCsm1 palm2 domain is almost identical to that of classical DNA polymerase Pol IV, and that the palm1 and B domains function as the other structural elements required (thumb and fingers) for DNA polymerase activity. MtbCsm1 polymerase activity is relatively weak in vitro and its functional relevance in vivo is unknown. Our structural and mutagenesis data suggest that residue K692 in the palm2 domain has been significant in the evolution of Csm1 from a polymerase to a cyclase, and support the notion that the cyclase activity of Csm1 requires the presence of other elements provided by the CRISPR/Cas effector complex. This structural rationale for Csm1 polymerase (alone) and cyclase (within the effector complex) activity should benefit future functional investigations and engineering.

Mycobacterium tuberculosis CRISPR/Cas system Csm1 holds clues to the evolutionary relationship between DNA polymerase and cyclase activity.,Zhang S, Li T, Huo Y, Yang J, Fleming J, Shi M, Wang Y, Wei W, Gu S, Bi L, Jiang T, Zhang H Int J Biol Macromol. 2020 Dec 28;170:140-149. doi:, 10.1016/j.ijbiomac.2020.12.014. PMID:33352158<ref>PMID:33352158</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 6kc0" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Huo Y]]
[[Category: Jiang T]]
[[Category: Li T]]