View source for 5m5i


==Pseudo-atomic model of microtubule-bound S.pombe kinesin-5 motor domain in the AMPPNP state (based on cryo-electron microscopy experiment): the N-terminus conformation allows formation of a cover neck bundle.==
<SX load='5m5i' size='340' side='right' viewer='molstar' caption='[[5m5i]], [[Resolution|resolution]] 9.30&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[5m5i]] is a 3 chain structure with sequence from [https://en.wikipedia.org/wiki/Bos_taurus Bos taurus] and [https://en.wikipedia.org/wiki/Schizosaccharomyces_pombe_972h- Schizosaccharomyces pombe 972h-]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5M5I OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=5M5I 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]] 9.3&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ANP:PHOSPHOAMINOPHOSPHONIC+ACID-ADENYLATE+ESTER'>ANP</scene>, <scene name='pdbligand=GDP:GUANOSINE-5-DIPHOSPHATE'>GDP</scene>, <scene name='pdbligand=GTP:GUANOSINE-5-TRIPHOSPHATE'>GTP</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene>, <scene name='pdbligand=TA1:TAXOL'>TA1</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=5m5i FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5m5i OCA], [https://pdbe.org/5m5i PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=5m5i RCSB], [https://www.ebi.ac.uk/pdbsum/5m5i PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=5m5i ProSAT]</span></td></tr>
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== Function ==
[https://www.uniprot.org/uniprot/TBA1D_BOVIN TBA1D_BOVIN] Tubulin is the major constituent of microtubules. It binds two moles of GTP, one at an exchangeable site on the beta chain and one at a non-exchangeable site on the alpha chain (By similarity).
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== Publication Abstract from PubMed ==
Cut7, the sole kinesin-5 in Schizosaccharomyces pombe, is essential for mitosis. Like other yeast kinesin-5 motors, Cut7 can reverse its stepping direction, by mechanisms that are currently unclear. Here we show that for full-length Cut7, the key determinant of stepping direction is the degree of motor crowding on the microtubule lattice, with greater crowding converting the motor from minus end-directed to plus end-directed stepping. To explain how high Cut7 occupancy causes this reversal, we postulate a simple proximity sensing mechanism that operates via steric blocking. We propose that the minus end-directed stepping action of Cut7 is selectively inhibited by collisions with neighbors under crowded conditions, whereas its plus end-directed action, being less space-hungry, is not. In support of this idea, we show that the direction of Cut7-driven microtubule sliding can be reversed by crowding it with non-Cut7 proteins. Thus, crowding by either dynein microtubule binding domain or Klp2, a kinesin-14, converts Cut7 from net minus end-directed to net plus end-directed stepping. Biochemical assays confirm that the Cut7 N terminus increases Cut7 occupancy by binding directly to microtubules. Direct observation by cryoEM reveals that this occupancy-enhancing N-terminal domain is partially ordered. Overall, our data point to a steric blocking mechanism for directional reversal through which collisions of Cut7 motor domains with their neighbors inhibit their minus end-directed stepping action, but not their plus end-directed stepping action. Our model can potentially reconcile a number of previous, apparently conflicting, observations and proposals for the reversal mechanism of yeast kinesins-5.

Schizosaccharomyces pombe kinesin-5 switches direction using a steric blocking mechanism.,Britto M, Goulet A, Rizvi S, von Loeffelholz O, Moores CA, Cross RA Proc Natl Acad Sci U S A. 2016 Nov 22;113(47):E7483-E7489. Epub 2016 Nov 9. PMID:27834216<ref>PMID:27834216</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 5m5i" style="background-color:#fffaf0;"></div>

==See Also==
*[[Kinesin 3D Structures|Kinesin 3D Structures]]
== References ==
<references/>
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[[Category: Bos taurus]]
[[Category: Large Structures]]
[[Category: Schizosaccharomyces pombe 972h-]]
[[Category: Cross RA]]
[[Category: Goulet A]]
[[Category: Moores CA]]