7sun: Difference between revisions

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<StructureSection load='7sun' size='340' side='right'caption='[[7sun]], [[Resolution|resolution]] 3.60&Aring;' scene=''>
<StructureSection load='7sun' size='340' side='right'caption='[[7sun]], [[Resolution|resolution]] 3.60&Aring;' scene=''>
== Structural highlights ==
== Structural highlights ==
<table><tr><td colspan='2'>[[7sun]] is a 2 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7SUN OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7SUN FirstGlance]. <br>
<table><tr><td colspan='2'>[[7sun]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Meriones_unguiculatus Meriones unguiculatus] and [https://en.wikipedia.org/wiki/Synthetic_construct Synthetic construct]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7SUN OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7SUN FirstGlance]. <br>
</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=7sun FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7sun OCA], [https://pdbe.org/7sun PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7sun RCSB], [https://www.ebi.ac.uk/pdbsum/7sun PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7sun ProSAT]</span></td></tr>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Electron Microscopy, [[Resolution|Resolution]] 3.6&#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=7sun FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7sun OCA], [https://pdbe.org/7sun PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7sun RCSB], [https://www.ebi.ac.uk/pdbsum/7sun PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7sun ProSAT]</span></td></tr>
</table>
</table>
== Function ==
== Function ==
[[https://www.uniprot.org/uniprot/S26A5_MERUN S26A5_MERUN]] Motor protein that converts auditory stimuli to length changes in outer hair cells and mediates sound amplification in the mammalian hearing organ. Prestin is a bidirectional voltage-to-force converter, it can operate at microsecond rates. It uses cytoplasmic anions as extrinsic voltage sensors, probably chloride and bicarbonate. After binding to a site with millimolar affinity, these anions are translocated across the membrane in response to changes in the transmembrane voltage. They move towards the extracellular surface following hyperpolarization, and towards the cytoplasmic side in response to depolarization. As a consequence, this translocation triggers conformational changes in the protein that ultimately alter its surface area in the plane of the plasma membrane. The area decreases when the anion is near the cytoplasmic face of the membrane (short state), and increases when the ion has crossed the membrane to the outer surface (long state). So, it acts as an incomplete transporter. It swings anions across the membrane, but does not allow these anions to dissociate and escape to the extracellular space. Salicylate, an inhibitor of outer hair cell motility, acts as competitive antagonist at the prestin anion-binding site (By similarity).  
[https://www.uniprot.org/uniprot/S26A5_MERUN S26A5_MERUN] Motor protein that converts auditory stimuli to length changes in outer hair cells and mediates sound amplification in the mammalian hearing organ. Prestin is a bidirectional voltage-to-force converter, it can operate at microsecond rates. It uses cytoplasmic anions as extrinsic voltage sensors, probably chloride and bicarbonate. After binding to a site with millimolar affinity, these anions are translocated across the membrane in response to changes in the transmembrane voltage. They move towards the extracellular surface following hyperpolarization, and towards the cytoplasmic side in response to depolarization. As a consequence, this translocation triggers conformational changes in the protein that ultimately alter its surface area in the plane of the plasma membrane. The area decreases when the anion is near the cytoplasmic face of the membrane (short state), and increases when the ion has crossed the membrane to the outer surface (long state). So, it acts as an incomplete transporter. It swings anions across the membrane, but does not allow these anions to dissociate and escape to the extracellular space. Salicylate, an inhibitor of outer hair cell motility, acts as competitive antagonist at the prestin anion-binding site (By similarity).[https://www.uniprot.org/uniprot/GFP_AEQVI GFP_AEQVI] Energy-transfer acceptor. Its role is to transduce the blue chemiluminescence of the protein aequorin into green fluorescent light by energy transfer. Fluoresces in vivo upon receiving energy from the Ca(2+)-activated photoprotein aequorin.
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
The mammalian outer hair cell (OHC) protein prestin (Slc26a5) differs from other Slc26 family members due to its unique piezoelectric-like property that drives OHC electromotility, the putative mechanism for cochlear amplification. Here, we use cryo-electron microscopy to determine prestin's structure at 3.6 A resolution. Prestin is structurally similar to the anion transporter Slc26a9. It is captured in an inward-open state which may reflect prestin's contracted state. Two well-separated transmembrane (TM) domains and two cytoplasmic sulfate transporter and anti-sigma factor antagonist (STAS) domains form a swapped dimer. The transmembrane domains consist of 14 transmembrane segments organized in two 7+7 inverted repeats, an architecture first observed in the bacterial symporter UraA. Mutation of prestin's chloride binding site removes salicylate competition with anions while retaining the prestin characteristic displacement currents (Nonlinear Capacitance), undermining the extrinsic voltage sensor hypothesis for prestin function.


Single particle cryo-EM structure of the outer hair cell motor protein prestin.,Butan C, Song Q, Bai JP, Tan WJT, Navaratnam D, Santos-Sacchi J Nat Commun. 2022 Jan 12;13(1):290. doi: 10.1038/s41467-021-27915-z. PMID:35022426<ref>PMID:35022426</ref>
==See Also==
 
*[[Prestin|Prestin]]
From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 7sun" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
__TOC__
</StructureSection>
</StructureSection>
[[Category: Large Structures]]
[[Category: Large Structures]]
[[Category: Butan, C]]
[[Category: Meriones unguiculatus]]
[[Category: Santos-Sacchi, J]]
[[Category: Synthetic construct]]
[[Category: Cochlear amplification]]
[[Category: Butan C]]
[[Category: Membrane protein]]
[[Category: Santos-Sacchi J]]
[[Category: Motor protein]]
[[Category: Nonlinear capacitance]]

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