1s16
From Proteopedia
(New page: 200px<br /><applet load="1s16" size="450" color="white" frame="true" align="right" spinBox="true" caption="1s16, resolution 2.1Å" /> '''Crystal Structure of ...) |
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| - | [[Image:1s16.gif|left|200px]]<br /><applet load="1s16" size=" | + | [[Image:1s16.gif|left|200px]]<br /><applet load="1s16" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1s16, resolution 2.1Å" /> | caption="1s16, resolution 2.1Å" /> | ||
'''Crystal Structure of E. coli Topoisomerase IV ParE 43kDa subunit complexed with ADPNP'''<br /> | '''Crystal Structure of E. coli Topoisomerase IV ParE 43kDa subunit complexed with ADPNP'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Topoisomerase IV and DNA gyrase are related bacterial type II | + | Topoisomerase IV and DNA gyrase are related bacterial type II topoisomerases that utilize the free energy from ATP hydrolysis to catalyze topological changes in the bacterial genome. The essential function of DNA gyrase is the introduction of negative DNA supercoils into the genome, whereas the essential function of topoisomerase IV is to decatenate daughter chromosomes following replication. Here, we report the crystal structures of a 43-kDa N-terminal fragment of Escherichia coli topoisomerase IV ParE subunit complexed with adenylyl-imidodiphosphate at 2.0-A resolution and a 24-kDa N-terminal fragment of the ParE subunit complexed with novobiocin at 2.1-A resolution. The solved ParE structures are strikingly similar to the known gyrase B (GyrB) subunit structures. We also identified single-position equivalent amino acid residues in ParE (M74) and in GyrB (I78) that, when exchanged, increased the potency of novobiocin against topoisomerase IV by nearly 20-fold (to 12 nM). The corresponding exchange in gyrase (I78 M) yielded a 20-fold decrease in the potency of novobiocin (to 1.0 micro M). These data offer an explanation for the observation that novobiocin is significantly less potent against topoisomerase IV than against DNA gyrase. Additionally, the enzyme kinetic parameters were affected. In gyrase, the ATP K(m) increased approximately 5-fold and the V(max) decreased approximately 30%. In contrast, the topoisomerase IV ATP K(m) decreased by a factor of 6, and the V(max) increased approximately 2-fold from the wild-type values. These data demonstrate that the ParE M74 and GyrB I78 side chains impart opposite effects on the enzyme's substrate affinity and catalytic efficiency. |
==About this Structure== | ==About this Structure== | ||
| - | 1S16 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with MG, SO4 and ANP as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | + | 1S16 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with <scene name='pdbligand=MG:'>MG</scene>, <scene name='pdbligand=SO4:'>SO4</scene> and <scene name='pdbligand=ANP:'>ANP</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1S16 OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Escherichia coli]] | [[Category: Escherichia coli]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Gross, C | + | [[Category: Gross, C H.]] |
[[Category: Wei, Y.]] | [[Category: Wei, Y.]] | ||
[[Category: ANP]] | [[Category: ANP]] | ||
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[[Category: two-domain protein complexed with adpnp]] | [[Category: two-domain protein complexed with adpnp]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:56:48 2008'' |
Revision as of 12:56, 21 February 2008
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Crystal Structure of E. coli Topoisomerase IV ParE 43kDa subunit complexed with ADPNP
Overview
Topoisomerase IV and DNA gyrase are related bacterial type II topoisomerases that utilize the free energy from ATP hydrolysis to catalyze topological changes in the bacterial genome. The essential function of DNA gyrase is the introduction of negative DNA supercoils into the genome, whereas the essential function of topoisomerase IV is to decatenate daughter chromosomes following replication. Here, we report the crystal structures of a 43-kDa N-terminal fragment of Escherichia coli topoisomerase IV ParE subunit complexed with adenylyl-imidodiphosphate at 2.0-A resolution and a 24-kDa N-terminal fragment of the ParE subunit complexed with novobiocin at 2.1-A resolution. The solved ParE structures are strikingly similar to the known gyrase B (GyrB) subunit structures. We also identified single-position equivalent amino acid residues in ParE (M74) and in GyrB (I78) that, when exchanged, increased the potency of novobiocin against topoisomerase IV by nearly 20-fold (to 12 nM). The corresponding exchange in gyrase (I78 M) yielded a 20-fold decrease in the potency of novobiocin (to 1.0 micro M). These data offer an explanation for the observation that novobiocin is significantly less potent against topoisomerase IV than against DNA gyrase. Additionally, the enzyme kinetic parameters were affected. In gyrase, the ATP K(m) increased approximately 5-fold and the V(max) decreased approximately 30%. In contrast, the topoisomerase IV ATP K(m) decreased by a factor of 6, and the V(max) increased approximately 2-fold from the wild-type values. These data demonstrate that the ParE M74 and GyrB I78 side chains impart opposite effects on the enzyme's substrate affinity and catalytic efficiency.
About this Structure
1S16 is a Single protein structure of sequence from Escherichia coli with , and as ligands. Full crystallographic information is available from OCA.
Reference
Crystal structures of Escherichia coli topoisomerase IV ParE subunit (24 and 43 kilodaltons): a single residue dictates differences in novobiocin potency against topoisomerase IV and DNA gyrase., Bellon S, Parsons JD, Wei Y, Hayakawa K, Swenson LL, Charifson PS, Lippke JA, Aldape R, Gross CH, Antimicrob Agents Chemother. 2004 May;48(5):1856-64. PMID:15105144
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