1xxi
From Proteopedia
(New page: 200px<br /><applet load="1xxi" size="450" color="white" frame="true" align="right" spinBox="true" caption="1xxi, resolution 4.1Å" /> '''ADP Bound E. coli Cla...) |
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| - | [[Image:1xxi.gif|left|200px]]<br /><applet load="1xxi" size=" | + | [[Image:1xxi.gif|left|200px]]<br /><applet load="1xxi" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1xxi, resolution 4.1Å" /> | caption="1xxi, resolution 4.1Å" /> | ||
'''ADP Bound E. coli Clamp Loader Complex'''<br /> | '''ADP Bound E. coli Clamp Loader Complex'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Clamp-loader complexes are heteropentameric AAA+ ATPases that load sliding | + | Clamp-loader complexes are heteropentameric AAA+ ATPases that load sliding clamps onto DNA. The structure of the nucleotide-free Escherichia coli clamp loader had been determined previously and led to the proposal that the clamp-loader cycles between an inactive state, in which the ATPase domains form a closed ring, and an active state that opens up to form a "C" shape. The crystal structure was interpreted as being closer to the active state than the inactive state. The crystal structure of a nucleotide-bound eukaryotic clamp loader [replication factor C (RFC)] revealed a different and more tightly packed spiral organization of the ATPase domains, raising questions about the significance of the conformation seen earlier for the bacterial clamp loader. We describe crystal structures of the E. coli clamp-loader complex bound to the ATP analog ATPgammaS (at a resolution of 3.5 A) and ADP (at a resolution of 4.1 A). These structures are similar to that of the nucleotide-free clamp-loader complex. Only two of the three functional ATP-binding sites are occupied by ATPgammaS or ADP in these structures, and the bound nucleotides make no interfacial contacts in the complex. These results, along with data from isothermal titration calorimetry, molecular dynamics simulations, and comparison with the RFC structure, suggest that the more open form of the E. coli clamp loader described earlier and in the present work corresponds to a stable inactive state of the clamp loader in which the ATPase domains are prevented from engaging the clamp in the highly cooperative manner seen in the fully ATP-loaded RFC-clamp structure. |
==About this Structure== | ==About this Structure== | ||
| - | 1XXI is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with PO4, ZN and ADP as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/DNA-directed_DNA_polymerase DNA-directed DNA polymerase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.7.7 2.7.7.7] Full crystallographic information is available from [http:// | + | 1XXI is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with <scene name='pdbligand=PO4:'>PO4</scene>, <scene name='pdbligand=ZN:'>ZN</scene> and <scene name='pdbligand=ADP:'>ADP</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/DNA-directed_DNA_polymerase DNA-directed DNA polymerase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.7.7 2.7.7.7] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1XXI OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Escherichia coli]] | [[Category: Escherichia coli]] | ||
[[Category: Protein complex]] | [[Category: Protein complex]] | ||
| - | [[Category: Donnell, M | + | [[Category: Donnell, M O.]] |
| - | [[Category: Kazmirski, S | + | [[Category: Kazmirski, S L.]] |
[[Category: Kuriyan, J.]] | [[Category: Kuriyan, J.]] | ||
[[Category: Podobnik, M.]] | [[Category: Podobnik, M.]] | ||
| - | [[Category: Weitze, T | + | [[Category: Weitze, T F.]] |
[[Category: ADP]] | [[Category: ADP]] | ||
[[Category: PO4]] | [[Category: PO4]] | ||
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[[Category: dna replication]] | [[Category: dna replication]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:59:41 2008'' |
Revision as of 13:59, 21 February 2008
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ADP Bound E. coli Clamp Loader Complex
Overview
Clamp-loader complexes are heteropentameric AAA+ ATPases that load sliding clamps onto DNA. The structure of the nucleotide-free Escherichia coli clamp loader had been determined previously and led to the proposal that the clamp-loader cycles between an inactive state, in which the ATPase domains form a closed ring, and an active state that opens up to form a "C" shape. The crystal structure was interpreted as being closer to the active state than the inactive state. The crystal structure of a nucleotide-bound eukaryotic clamp loader [replication factor C (RFC)] revealed a different and more tightly packed spiral organization of the ATPase domains, raising questions about the significance of the conformation seen earlier for the bacterial clamp loader. We describe crystal structures of the E. coli clamp-loader complex bound to the ATP analog ATPgammaS (at a resolution of 3.5 A) and ADP (at a resolution of 4.1 A). These structures are similar to that of the nucleotide-free clamp-loader complex. Only two of the three functional ATP-binding sites are occupied by ATPgammaS or ADP in these structures, and the bound nucleotides make no interfacial contacts in the complex. These results, along with data from isothermal titration calorimetry, molecular dynamics simulations, and comparison with the RFC structure, suggest that the more open form of the E. coli clamp loader described earlier and in the present work corresponds to a stable inactive state of the clamp loader in which the ATPase domains are prevented from engaging the clamp in the highly cooperative manner seen in the fully ATP-loaded RFC-clamp structure.
About this Structure
1XXI is a Protein complex structure of sequences from Escherichia coli with , and as ligands. Active as DNA-directed DNA polymerase, with EC number 2.7.7.7 Full crystallographic information is available from OCA.
Reference
Structural analysis of the inactive state of the Escherichia coli DNA polymerase clamp-loader complex., Kazmirski SL, Podobnik M, Weitze TF, O'Donnell M, Kuriyan J, Proc Natl Acad Sci U S A. 2004 Nov 30;101(48):16750-5. Epub 2004 Nov 19. PMID:15556993
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