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New page: left|200px<br /><applet load="1e54" size="450" color="white" frame="true" align="right" spinBox="true" caption="1e54, resolution 2.1Å" /> '''ANION-SELECTIVE PORIN... |
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== | ==Anion-selective porin from Comamonas acidovorans== | ||
BACKGROUND: Porins provide diffusion channels for salts and small organic | <StructureSection load='1e54' size='340' side='right'caption='[[1e54]], [[Resolution|resolution]] 2.10Å' scene=''> | ||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[1e54]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Delftia_acidovorans Delftia acidovorans]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1E54 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1E54 FirstGlance]. <br> | |||
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.1Å</td></tr> | |||
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=PCA:PYROGLUTAMIC+ACID'>PCA</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene></td></tr> | |||
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1e54 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1e54 OCA], [https://pdbe.org/1e54 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1e54 RCSB], [https://www.ebi.ac.uk/pdbsum/1e54 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1e54 ProSAT]</span></td></tr> | |||
</table> | |||
== Function == | |||
[https://www.uniprot.org/uniprot/OMP32_DELAC OMP32_DELAC] | |||
== Evolutionary Conservation == | |||
[[Image:Consurf_key_small.gif|200px|right]] | |||
Check<jmol> | |||
<jmolCheckbox> | |||
<scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/e5/1e54_consurf.spt"</scriptWhenChecked> | |||
<scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.spt</scriptWhenUnchecked> | |||
<text>to colour the structure by Evolutionary Conservation</text> | |||
</jmolCheckbox> | |||
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=1e54 ConSurf]. | |||
<div style="clear:both"></div> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
BACKGROUND: Porins provide diffusion channels for salts and small organic molecules in the outer membrane of bacteria. In OmpF from Escherichia coli and related porins, an electrostatic field across the channel and a potential, originating from a surplus of negative charges, create moderate cation selectivity. Here, we investigate the strongly anion-selective porin Omp32 from Comamonas acidovorans, which is closely homologous to the porins of pathogenic Bordetella and Neisseria species. RESULTS: The crystal structure of Omp32 was determined to a resolution of 2.1 A using single isomorphous replacement with anomalous scattering (SIRAS). The porin consists of a 16-stranded beta barrel with eight external loops and seven periplasmic turns. Loops 3 and 8, together with a protrusion located within beta-strand 2, narrow the cross-section of the pore considerably. Arginine residues create a charge filter in the constriction zone and a positive surface potential at the external and periplasmic faces. One sulfate ion was bound to Arg38 in the channel constriction zone. A peptide of 5.8 kDa appeared bound to Omp32 in a 1:1 stoichiometry on the periplasmic side close to the symmetry axis of the trimer. Eight amino acids of this peptide could be identified, revealing specific interactions with beta-strand 1 of the porin. CONCLUSIONS: The Omp32 structure explains the strong anion selectivity of this porin. Selectivity is conferred by a positive potential, which is not attenuated by negative charges inside the channel, and by an extremely narrow constriction zone. Moreover, Omp32 represents the anchor molecule for a peptide which is homologous to proteins that link the outer membrane to the cell wall peptidoglycan. | |||
Crystal structure of Omp32, the anion-selective porin from Comamonas acidovorans, in complex with a periplasmic peptide at 2.1 A resolution.,Zeth K, Diederichs K, Welte W, Engelhardt H Structure. 2000 Sep 15;8(9):981-92. PMID:10986465<ref>PMID:10986465</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
<div class="pdbe-citations 1e54" style="background-color:#fffaf0;"></div> | |||
==See Also== | |||
*[[Porin 3D structures|Porin 3D structures]] | |||
== References == | |||
<references/> | |||
__TOC__ | |||
</StructureSection> | |||
[[Category: Delftia acidovorans]] | [[Category: Delftia acidovorans]] | ||
[[Category: | [[Category: Large Structures]] | ||
[[Category: Diederichs | [[Category: Diederichs K]] | ||
[[Category: Engelhardt | [[Category: Engelhardt H]] | ||
[[Category: Welte | [[Category: Welte W]] | ||
[[Category: Zeth | [[Category: Zeth K]] | ||
Latest revision as of 07:28, 17 October 2024
Anion-selective porin from Comamonas acidovoransAnion-selective porin from Comamonas acidovorans
Structural highlights
FunctionEvolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedBACKGROUND: Porins provide diffusion channels for salts and small organic molecules in the outer membrane of bacteria. In OmpF from Escherichia coli and related porins, an electrostatic field across the channel and a potential, originating from a surplus of negative charges, create moderate cation selectivity. Here, we investigate the strongly anion-selective porin Omp32 from Comamonas acidovorans, which is closely homologous to the porins of pathogenic Bordetella and Neisseria species. RESULTS: The crystal structure of Omp32 was determined to a resolution of 2.1 A using single isomorphous replacement with anomalous scattering (SIRAS). The porin consists of a 16-stranded beta barrel with eight external loops and seven periplasmic turns. Loops 3 and 8, together with a protrusion located within beta-strand 2, narrow the cross-section of the pore considerably. Arginine residues create a charge filter in the constriction zone and a positive surface potential at the external and periplasmic faces. One sulfate ion was bound to Arg38 in the channel constriction zone. A peptide of 5.8 kDa appeared bound to Omp32 in a 1:1 stoichiometry on the periplasmic side close to the symmetry axis of the trimer. Eight amino acids of this peptide could be identified, revealing specific interactions with beta-strand 1 of the porin. CONCLUSIONS: The Omp32 structure explains the strong anion selectivity of this porin. Selectivity is conferred by a positive potential, which is not attenuated by negative charges inside the channel, and by an extremely narrow constriction zone. Moreover, Omp32 represents the anchor molecule for a peptide which is homologous to proteins that link the outer membrane to the cell wall peptidoglycan. Crystal structure of Omp32, the anion-selective porin from Comamonas acidovorans, in complex with a periplasmic peptide at 2.1 A resolution.,Zeth K, Diederichs K, Welte W, Engelhardt H Structure. 2000 Sep 15;8(9):981-92. PMID:10986465[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences |
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