1ab4: Difference between revisions
New page: left|200px<br /><applet load="1ab4" size="450" color="white" frame="true" align="right" spinBox="true" caption="1ab4, resolution 2.8Å" /> '''59KDA FRAGMENT OF GYR... |
No edit summary |
||
| Line 1: | Line 1: | ||
[[Image:1ab4.gif|left|200px]]<br /><applet load="1ab4" size=" | [[Image:1ab4.gif|left|200px]]<br /><applet load="1ab4" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="1ab4, resolution 2.8Å" /> | caption="1ab4, resolution 2.8Å" /> | ||
'''59KDA FRAGMENT OF GYRASE A FROM E. COLI'''<br /> | '''59KDA FRAGMENT OF GYRASE A FROM E. COLI'''<br /> | ||
==Overview== | ==Overview== | ||
DNA gyrase is a type II DNA topoisomerase from bacteria that introduces | DNA gyrase is a type II DNA topoisomerase from bacteria that introduces supercoils into DNA. It catalyses the breakage of a DNA duplex (the G segment), the passage of another segment (the T segment) through the break, and then the reunification of the break. This activity involves the opening and dosing of a series of molecular 'gates' which is coupled to ATP hydrolysis. Here we present the crystal structure of the 'breakage-reunion' domain of the gyrase at 2.8 A resolution. Comparison of the structure of this 59K (relative molecular mass, 59,000) domain with that of a 92K fragment of yeast topoisomerase II reveals a very different quaternary organization, and we propose that the two structures represent two principal conformations that participate in the enzymatic pathway. The gyrase structure reveals a new dimer contact with a grooved concave surface for binding the G segment and a cluster of conserved charged residues surrounding the active-site tyrosines. It also shows how breakage of the G segment can occur and, together with the topoisomerase II structure, suggests a pathway by which the T segment can be released through the second gate of the enzyme. Mutations that confer resistance to the quinolone antibacterial agents cluster at the new dimer interface, indicating how these drugs might interact with the gyrase-DNA complex. | ||
==About this Structure== | ==About this Structure== | ||
1AB4 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Active as [http://en.wikipedia.org/wiki/DNA_topoisomerase_(ATP-hydrolyzing) DNA topoisomerase (ATP-hydrolyzing)], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=5.99.1.3 5.99.1.3] Full crystallographic information is available from [http:// | 1AB4 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Active as [http://en.wikipedia.org/wiki/DNA_topoisomerase_(ATP-hydrolyzing) DNA topoisomerase (ATP-hydrolyzing)], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=5.99.1.3 5.99.1.3] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1AB4 OCA]. | ||
==Reference== | ==Reference== | ||
| Line 14: | Line 14: | ||
[[Category: Escherichia coli]] | [[Category: Escherichia coli]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Cabral, J | [[Category: Cabral, J H.M.]] | ||
[[Category: Liddington, R | [[Category: Liddington, R C.]] | ||
[[Category: Maxwell, A.]] | [[Category: Maxwell, A.]] | ||
[[Category: gyrase]] | [[Category: gyrase]] | ||
| Line 21: | Line 21: | ||
[[Category: topoisomerase ii]] | [[Category: topoisomerase ii]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 11:42:44 2008'' | ||
Revision as of 12:42, 21 February 2008
|
59KDA FRAGMENT OF GYRASE A FROM E. COLI
OverviewOverview
DNA gyrase is a type II DNA topoisomerase from bacteria that introduces supercoils into DNA. It catalyses the breakage of a DNA duplex (the G segment), the passage of another segment (the T segment) through the break, and then the reunification of the break. This activity involves the opening and dosing of a series of molecular 'gates' which is coupled to ATP hydrolysis. Here we present the crystal structure of the 'breakage-reunion' domain of the gyrase at 2.8 A resolution. Comparison of the structure of this 59K (relative molecular mass, 59,000) domain with that of a 92K fragment of yeast topoisomerase II reveals a very different quaternary organization, and we propose that the two structures represent two principal conformations that participate in the enzymatic pathway. The gyrase structure reveals a new dimer contact with a grooved concave surface for binding the G segment and a cluster of conserved charged residues surrounding the active-site tyrosines. It also shows how breakage of the G segment can occur and, together with the topoisomerase II structure, suggests a pathway by which the T segment can be released through the second gate of the enzyme. Mutations that confer resistance to the quinolone antibacterial agents cluster at the new dimer interface, indicating how these drugs might interact with the gyrase-DNA complex.
About this StructureAbout this Structure
1AB4 is a Single protein structure of sequence from Escherichia coli. Active as DNA topoisomerase (ATP-hydrolyzing), with EC number 5.99.1.3 Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of the breakage-reunion domain of DNA gyrase., Morais Cabral JH, Jackson AP, Smith CV, Shikotra N, Maxwell A, Liddington RC, Nature. 1997 Aug 28;388(6645):903-6. PMID:9278055
Page seeded by OCA on Thu Feb 21 11:42:44 2008