1s52: Difference between revisions
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== | ==Thr24Val Bacteriorhodopsin== | ||
<StructureSection load='1s52' size='340' side='right'caption='[[1s52]], [[Resolution|resolution]] 2.30Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[1s52]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Halobacterium_salinarum Halobacterium salinarum]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1S52 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1S52 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]] 2.3Å</td></tr> | |||
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=RET:RETINAL'>RET</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=1s52 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1s52 OCA], [https://pdbe.org/1s52 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1s52 RCSB], [https://www.ebi.ac.uk/pdbsum/1s52 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1s52 ProSAT]</span></td></tr> | |||
</table> | |||
== Function == | |||
[https://www.uniprot.org/uniprot/BACR_HALSA BACR_HALSA] Light-driven proton pump. | |||
== 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/s5/1s52_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=1s52 ConSurf]. | |||
<div style="clear:both"></div> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
Hydrogen bonds involving a carbon donor are very common in protein structures, and energy calculations suggest that Calpha-H...O hydrogen bonds could be about one-half the strength of traditional hydrogen bonds. It has therefore been proposed that these nontraditional hydrogen bonds could be a significant factor in stabilizing proteins, particularly membrane proteins as there is a low dielectric and no competition from water in the bilayer core. Nevertheless, this proposition has never been tested experimentally. Here, we report an experimental test of the significance of Calpha-H...O bonds for protein stability. Thr24 in bacteriorhodopsin, which makes an interhelical Calpha-H...O hydrogen bond to the Calpha of Ala51, was changed to Ala, Val, and Ser, and the thermodynamic stability of the mutants was measured. None of the mutants had significantly reduced stability. In fact, T24A was more stable than the wild-type protein by 0.6 kcal/mol. Crystal structures were determined for each of the mutants, and, while some structural changes were seen for T24S and T24V, T24A showed essentially no apparent structural alteration that could account for the increased stability. Thus, Thr24 appears to destabilize the protein rather than stabilize. Our results suggest that Calpha-H...O bonds are not a major contributor to protein stability. | Hydrogen bonds involving a carbon donor are very common in protein structures, and energy calculations suggest that Calpha-H...O hydrogen bonds could be about one-half the strength of traditional hydrogen bonds. It has therefore been proposed that these nontraditional hydrogen bonds could be a significant factor in stabilizing proteins, particularly membrane proteins as there is a low dielectric and no competition from water in the bilayer core. Nevertheless, this proposition has never been tested experimentally. Here, we report an experimental test of the significance of Calpha-H...O bonds for protein stability. Thr24 in bacteriorhodopsin, which makes an interhelical Calpha-H...O hydrogen bond to the Calpha of Ala51, was changed to Ala, Val, and Ser, and the thermodynamic stability of the mutants was measured. None of the mutants had significantly reduced stability. In fact, T24A was more stable than the wild-type protein by 0.6 kcal/mol. Crystal structures were determined for each of the mutants, and, while some structural changes were seen for T24S and T24V, T24A showed essentially no apparent structural alteration that could account for the increased stability. Thus, Thr24 appears to destabilize the protein rather than stabilize. Our results suggest that Calpha-H...O bonds are not a major contributor to protein stability. | ||
A C alpha-H...O hydrogen bond in a membrane protein is not stabilizing.,Yohannan S, Faham S, Yang D, Grosfeld D, Chamberlain AK, Bowie JU J Am Chem Soc. 2004 Mar 3;126(8):2284-5. PMID:14982414<ref>PMID:14982414</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
<div class="pdbe-citations 1s52" style="background-color:#fffaf0;"></div> | |||
==See Also== | |||
*[[Bacteriorhodopsin 3D structures|Bacteriorhodopsin 3D structures]] | |||
== References == | |||
<references/> | |||
__TOC__ | |||
</StructureSection> | |||
[[Category: Halobacterium salinarum]] | [[Category: Halobacterium salinarum]] | ||
[[Category: | [[Category: Large Structures]] | ||
[[Category: Bowie | [[Category: Bowie JU]] | ||
[[Category: Chamberlain | [[Category: Chamberlain AK]] | ||
[[Category: Faham | [[Category: Faham S]] | ||
[[Category: Grosfeld | [[Category: Grosfeld D]] | ||
[[Category: Yang | [[Category: Yang D]] | ||
[[Category: Yohannan | [[Category: Yohannan S]] | ||