View source for 4ckk


==Apo structure of 55 kDa N-terminal domain of E. coli DNA gyrase A subunit==
<StructureSection load='4ckk' size='340' side='right'caption='[[4ckk]], [[Resolution|resolution]] 1.90&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4ckk]] is a 4 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=4CKK OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4CKK 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]] 1.9&#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=4ckk FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4ckk OCA], [https://pdbe.org/4ckk PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4ckk RCSB], [https://www.ebi.ac.uk/pdbsum/4ckk PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4ckk ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/A0A0H3JH39_ECO57 A0A0H3JH39_ECO57] A type II topoisomerase that negatively supercoils closed circular double-stranded (ds) DNA in an ATP-dependent manner to modulate DNA topology and maintain chromosomes in an underwound state. Negative supercoiling favors strand separation, and DNA replication, transcription, recombination and repair, all of which involve strand separation. Also able to catalyze the interconversion of other topological isomers of dsDNA rings, including catenanes and knotted rings. Type II topoisomerases break and join 2 DNA strands simultaneously in an ATP-dependent manner.[HAMAP-Rule:MF_01897]
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Simocyclinone D8 (SD8) is an antibiotic produced by Streptomyces antibioticus that targets DNA gyrase. A previous structure of SD8 complexed with the N-terminal domain of the DNA gyrase A protein (GyrA) suggested that four SD8 molecules stabilised a tetramer of the protein; subsequent mass-spectrometry experiments suggested that a protein dimer with two symmetry-related SD8s was more likely. This work describes the structures of a further truncated form of the GyrA N-terminal domain fragment with and without SD8 bound. The structure with SD8 has the two SD8 molecules bound within the same GyrA dimer. This new structure is entirely consistent with the mutations in GyrA that confer SD8 resistance and, by comparison with a new apo structure of the GyrA N-terminal domain, reveals the likely conformation changes that occur upon SD8 binding, and the detailed mechanism of SD8 inhibition of gyrase. Isothermal titration calorimetry experiments are consistent with the crystallography results and further suggest that a previously observed complex between SD8 and GyrB is ~1000-fold weaker than the interaction with GyrA.

A new crystal structure of the bifunctional antibiotic simocyclinone D8 bound to DNA gyrase gives fresh insight into the mechanism of inhibition.,Hearnshaw SJ, Edwards MJ, Stevenson CE, Lawson DM, Maxwell A J Mol Biol. 2014 Mar 1. pii: S0022-2836(14)00099-0. doi:, 10.1016/j.jmb.2014.02.017. PMID:24594357<ref>PMID:24594357</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 4ckk" style="background-color:#fffaf0;"></div>

==See Also==
*[[Gyrase 3D Structures|Gyrase 3D Structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Escherichia coli]]
[[Category: Large Structures]]
[[Category: Edwards MJ]]
[[Category: Hearnshaw SJ]]
[[Category: Lawson DM]]
[[Category: Maxwell A]]
[[Category: Stevenson CEM]]