2aco: Difference between revisions
New page: left|200px<br /><applet load="2aco" size="450" color="white" frame="true" align="right" spinBox="true" caption="2aco, resolution 1.80Å" /> '''Xray structure of Bl... |
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[[Image:2aco.gif|left|200px]]<br /><applet load="2aco" size=" | [[Image:2aco.gif|left|200px]]<br /><applet load="2aco" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="2aco, resolution 1.80Å" /> | caption="2aco, resolution 1.80Å" /> | ||
'''Xray structure of Blc dimer in complex with vaccenic acid'''<br /> | '''Xray structure of Blc dimer in complex with vaccenic acid'''<br /> | ||
==Overview== | ==Overview== | ||
Lipocalins, a widespread multifunctional family of small proteins | Lipocalins, a widespread multifunctional family of small proteins (15-25kDa) have been first described in eukaryotes and more recently in Gram-negative bacteria. Bacterial lipocalins belonging to class I are outer membrane lipoproteins, among which Blc from E. coli is the better studied. Blc is expressed under conditions of starvation and high osmolarity, conditions known to exert stress on the cell envelope. The structure of Blc that we have previously solved (V. Campanacci, D. Nurizzo, S. Spinelli, C. Valencia, M. Tegoni, C. Cambillau, FEBS Lett. 562 (2004) 183-188.) suggested its possible role in binding fatty acids or phospholipids. Both physiological and structural data on Blc, therefore, point to a role in storage or transport of lipids necessary for membrane maintenance. In order to further document this hypothesis for Blc function, we have performed binding studies using fluorescence quenching experiments. Our results indicate that dimeric Blc binds fatty acids and phospholipids in a micromolar K(d) range. The crystal structure of Blc with vaccenic acid, an unsaturated C18 fatty acid, reveals that the binding site spans across the Blc dimer, opposite to its membrane anchored face. An exposed unfilled pocket seemingly suited to bind a polar group attached to the fatty acid prompted us to investigate lyso-phospholipids, which were found to bind in a nanomolar K(d) range. We discuss these findings in terms of a potential role for Blc in the metabolism of lysophospholipids generated in the bacterial outer membrane. | ||
==About this Structure== | ==About this Structure== | ||
2ACO 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 VCA as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http:// | 2ACO 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=VCA:'>VCA</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2ACO OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Escherichia coli]] | [[Category: Escherichia coli]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Bishop, R | [[Category: Bishop, R E.]] | ||
[[Category: Blangy, S.]] | [[Category: Blangy, S.]] | ||
[[Category: Cambillau, C.]] | [[Category: Cambillau, C.]] | ||
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[[Category: Tegoni, M.]] | [[Category: Tegoni, M.]] | ||
[[Category: VCA]] | [[Category: VCA]] | ||
[[Category: e | [[Category: e coli]] | ||
[[Category: fatty acid]] | [[Category: fatty acid]] | ||
[[Category: lipocalin]] | [[Category: lipocalin]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:26:02 2008'' | ||
Revision as of 17:26, 21 February 2008
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Xray structure of Blc dimer in complex with vaccenic acid
OverviewOverview
Lipocalins, a widespread multifunctional family of small proteins (15-25kDa) have been first described in eukaryotes and more recently in Gram-negative bacteria. Bacterial lipocalins belonging to class I are outer membrane lipoproteins, among which Blc from E. coli is the better studied. Blc is expressed under conditions of starvation and high osmolarity, conditions known to exert stress on the cell envelope. The structure of Blc that we have previously solved (V. Campanacci, D. Nurizzo, S. Spinelli, C. Valencia, M. Tegoni, C. Cambillau, FEBS Lett. 562 (2004) 183-188.) suggested its possible role in binding fatty acids or phospholipids. Both physiological and structural data on Blc, therefore, point to a role in storage or transport of lipids necessary for membrane maintenance. In order to further document this hypothesis for Blc function, we have performed binding studies using fluorescence quenching experiments. Our results indicate that dimeric Blc binds fatty acids and phospholipids in a micromolar K(d) range. The crystal structure of Blc with vaccenic acid, an unsaturated C18 fatty acid, reveals that the binding site spans across the Blc dimer, opposite to its membrane anchored face. An exposed unfilled pocket seemingly suited to bind a polar group attached to the fatty acid prompted us to investigate lyso-phospholipids, which were found to bind in a nanomolar K(d) range. We discuss these findings in terms of a potential role for Blc in the metabolism of lysophospholipids generated in the bacterial outer membrane.
About this StructureAbout this Structure
2ACO is a Single protein structure of sequence from Escherichia coli with as ligand. Full crystallographic information is available from OCA.
ReferenceReference
The membrane bound bacterial lipocalin Blc is a functional dimer with binding preference for lysophospholipids., Campanacci V, Bishop RE, Blangy S, Tegoni M, Cambillau C, FEBS Lett. 2006 Sep 4;580(20):4877-83. Epub 2006 Aug 10. PMID:16920109
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