2ibm
From Proteopedia
(New page: 200px<br /><applet load="2ibm" size="450" color="white" frame="true" align="right" spinBox="true" caption="2ibm, resolution 3.20Å" /> '''A novel dimer interf...) |
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| - | [[Image:2ibm.gif|left|200px]]<br /><applet load="2ibm" size=" | + | [[Image:2ibm.gif|left|200px]]<br /><applet load="2ibm" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="2ibm, resolution 3.20Å" /> | caption="2ibm, resolution 3.20Å" /> | ||
'''A novel dimer interface and conformational changes revealed by an X-ray structure of B. subtilis SecA'''<br /> | '''A novel dimer interface and conformational changes revealed by an X-ray structure of B. subtilis SecA'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The SecA ATPase moves polypeptides post-translationally across the plasma | + | The SecA ATPase moves polypeptides post-translationally across the plasma membrane of eubacteria, but the mechanism of transport is still unclear. We describe the crystal structure of a novel dimeric form of Bacillus subtilis SecA. Dimerization of SecA occurs at the prominent groove formed by the nucleotide binding domain 2 (nbd2) and the preprotein cross-linking (ppx) domain. The dimer interface is very large, burying approximately 5400 A(2) of solvent accessible surface per monomer. Single cysteine disulfide cross-linking shows the presence of this novel SecA dimer in solution. In addition, other dimers also exist in solution, arguing that they all are in equilibrium with monomeric SecA and supporting the idea that the monomer may be the functional species. Dimerization of SecA causes an alpha-helix of one subunit to convert to a short beta-strand that participates in beta-sheet formation with strands in the other subunit. This conversion of secondary structure elements occurs close to the connection between the nbd1 and ppx domains, a potential site of interaction with translocation substrate. Comparing the different X-ray structures of B. subtilis SecA suggests that small changes in the nucleotide binding domains could be amplified via helix 1 of the helical scaffold domain (hsd) to generate larger movements of the domains involved in polypeptide binding. |
==About this Structure== | ==About this Structure== | ||
| - | 2IBM is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacillus_subtilis Bacillus subtilis] with ADP as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http:// | + | 2IBM is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacillus_subtilis Bacillus subtilis] with <scene name='pdbligand=ADP:'>ADP</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2IBM OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Li, W.]] | [[Category: Li, W.]] | ||
| - | [[Category: Rapoport, T | + | [[Category: Rapoport, T A.]] |
[[Category: Zimmer, J.]] | [[Category: Zimmer, J.]] | ||
[[Category: ADP]] | [[Category: ADP]] | ||
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[[Category: signal peptide binding]] | [[Category: signal peptide binding]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 17:50:55 2008'' |
Revision as of 15:50, 21 February 2008
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A novel dimer interface and conformational changes revealed by an X-ray structure of B. subtilis SecA
Overview
The SecA ATPase moves polypeptides post-translationally across the plasma membrane of eubacteria, but the mechanism of transport is still unclear. We describe the crystal structure of a novel dimeric form of Bacillus subtilis SecA. Dimerization of SecA occurs at the prominent groove formed by the nucleotide binding domain 2 (nbd2) and the preprotein cross-linking (ppx) domain. The dimer interface is very large, burying approximately 5400 A(2) of solvent accessible surface per monomer. Single cysteine disulfide cross-linking shows the presence of this novel SecA dimer in solution. In addition, other dimers also exist in solution, arguing that they all are in equilibrium with monomeric SecA and supporting the idea that the monomer may be the functional species. Dimerization of SecA causes an alpha-helix of one subunit to convert to a short beta-strand that participates in beta-sheet formation with strands in the other subunit. This conversion of secondary structure elements occurs close to the connection between the nbd1 and ppx domains, a potential site of interaction with translocation substrate. Comparing the different X-ray structures of B. subtilis SecA suggests that small changes in the nucleotide binding domains could be amplified via helix 1 of the helical scaffold domain (hsd) to generate larger movements of the domains involved in polypeptide binding.
About this Structure
2IBM is a Single protein structure of sequence from Bacillus subtilis with as ligand. Full crystallographic information is available from OCA.
Reference
A novel dimer interface and conformational changes revealed by an X-ray structure of B. subtilis SecA., Zimmer J, Li W, Rapoport TA, J Mol Biol. 2006 Dec 1;364(3):259-65. Epub 2006 Aug 22. PMID:16989859
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