View source for 1uun


==Main porin from Mycobacterium smegmatis (MspA)==
<StructureSection load='1uun' size='340' side='right'caption='[[1uun]], [[Resolution|resolution]] 2.50&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1uun]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Mycolicibacterium_smegmatis Mycolicibacterium smegmatis]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1UUN OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1UUN 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]] 2.5&#8491;</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=1uun FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1uun OCA], [https://pdbe.org/1uun PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1uun RCSB], [https://www.ebi.ac.uk/pdbsum/1uun PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1uun ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/MSPA_MYCS2 MSPA_MYCS2] The major porin in this organism, forms a water-filled channel which favors the permeation of cations, amino acids, iron Fe(3+) and less efficiently phosphate. Does not transport Fe-ExoMS, the predominant siderophore. Plays a role in transport of beta-lactamase and hydrophilic fluoroquinolone antibiotics such as norfloxacin as well as chloramphenicol. There are about 2400 porins in wild-type, 800 in an mspA deletion and 150 in a double mspA-mspC deletion. Different conductance values with maxima at 2.3 and 4.6 nanosiemens might be caused by a simultaneous reconstitution of MspA channels into the membrane or by the existence of different MspA conformations.<ref>PMID:10476028</ref> <ref>PMID:16238622</ref> <ref>PMID:17209034</ref> <ref>PMID:18559650</ref> <ref>PMID:20952578</ref> 
== 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/uu/1uun_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.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=1uun ConSurf].
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== Publication Abstract from PubMed ==
Mycobacteria have low-permeability outer membranes that render them resistant to most antibiotics. Hydrophilic nutrients can enter by way of transmembrane-channel proteins called porins. An x-ray analysis of the main porin from Mycobacterium smegmatis, MspA, revealed a homooctameric goblet-like conformation with a single central channel. This is the first structure of a mycobacterial outer-membrane protein. No structure-related protein was found in the Protein Data Bank. MspA contains two consecutive beta barrels with nonpolar outer surfaces that form a ribbon around the porin, which is too narrow to fit the thickness of the mycobacterial outer membrane in contemporary models.

The structure of a mycobacterial outer-membrane channel.,Faller M, Niederweis M, Schulz GE Science. 2004 Feb 20;303(5661):1189-92. PMID:14976314<ref>PMID:14976314</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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==See Also==
*[[Porin 3D structures|Porin 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Mycolicibacterium smegmatis]]
[[Category: Faller M]]
[[Category: Niederweis M]]
[[Category: Schulz GE]]