View source for 2w4w


==Isometrically contracting insect asynchronous flight muscle quick frozen after a quick stretch step==
<SX load='2w4w' size='340' side='right' viewer='molstar' caption='[[2w4w]], [[Resolution|resolution]] 35.00&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[2w4w]] is a 3 chain structure with sequence from [https://en.wikipedia.org/wiki/Argopecten_irradians Argopecten irradians]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2W4W OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2W4W FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Electron Microscopy, [[Resolution|Resolution]] 35&#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=2w4w FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2w4w OCA], [https://pdbe.org/2w4w PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2w4w RCSB], [https://www.ebi.ac.uk/pdbsum/2w4w PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2w4w ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/MYS_ARGIR MYS_ARGIR] Muscle contraction.  Myosin is a protein that binds to F-actin and has ATPase activity that is activated by F-actin.
== 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/w4/2w4w_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=2w4w ConSurf].
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== Publication Abstract from PubMed ==
The application of rapidly applied length steps to actively contracting muscle is a classic method for synchronizing the response of myosin cross-bridges so that the average response of the ensemble can be measured. Alternatively, electron tomography (ET) is a technique that can report the structure of the individual members of the ensemble. We probed the structure of active myosin motors (cross-bridges) by applying 0.5% changes in length (either a stretch or a release) within 2 ms to isometrically contracting insect flight muscle (IFM) fibers followed after 5-6 ms by rapid freezing against a liquid helium cooled copper mirror. ET of freeze-substituted fibers, embedded and thin-sectioned, provides 3-D cross-bridge images, sorted by multivariate data analysis into approximately 40 classes, distinct in average structure, population size and lattice distribution. Individual actin subunits are resolved facilitating quasi-atomic modeling of each class average to determine its binding strength (weak or strong) to actin. approximately 98% of strong-binding acto-myosin attachments present after a length perturbation are confined to "target zones" of only two actin subunits located exactly midway between successive troponin complexes along each long-pitch helical repeat of actin. Significant changes in the types, distribution and structure of actin-myosin attachments occurred in a manner consistent with the mechanical transients. Most dramatic is near disappearance, after either length perturbation, of a class of weak-binding cross-bridges, attached within the target zone, that are highly likely to be precursors of strong-binding cross-bridges. These weak-binding cross-bridges were originally observed in isometrically contracting IFM. Their disappearance following a quick stretch or release can be explained by a recent kinetic model for muscle contraction, as behaviour consistent with their identification as precursors of strong-binding cross-bridges. The results provide a detailed model for contraction in IFM that may be applicable to contraction in other types of muscle.

Structural Changes in Isometrically Contracting Insect Flight Muscle Trapped following a Mechanical Perturbation.,Wu S, Liu J, Reedy MC, Perz-Edwards RJ, Tregear RT, Winkler H, Franzini-Armstrong C, Sasaki H, Lucaveche C, Goldman YE, Reedy MK, Taylor KA PLoS One. 2012;7(6):e39422. Epub 2012 Jun 25. PMID:22761792<ref>PMID:22761792</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 2w4w" style="background-color:#fffaf0;"></div>

==See Also==
*[[Myosin 3D Structures|Myosin 3D Structures]]
== References ==
<references/>
__TOC__
</SX>
[[Category: Argopecten irradians]]
[[Category: Large Structures]]
[[Category: Franzini-Armstrong C]]
[[Category: Goldman YE]]
[[Category: Liu J]]
[[Category: Lucaveche C]]
[[Category: Reedy MC]]
[[Category: Reedy MK]]
[[Category: Sasaki H]]
[[Category: Taylor KA]]
[[Category: Tregear RT]]
[[Category: Winkler H]]
[[Category: Wu S]]