View source for 1ahr


==CALMODULIN MUTANT WITH A TWO RESIDUE DELETION IN THE CENTRAL HELIX==
<StructureSection load='1ahr' size='340' side='right'caption='[[1ahr]], [[Resolution|resolution]] 1.80&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1ahr]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Gallus_gallus Gallus gallus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1AHR OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1AHR 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]] 1.8&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</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=1ahr FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1ahr OCA], [https://pdbe.org/1ahr PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1ahr RCSB], [https://www.ebi.ac.uk/pdbsum/1ahr PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1ahr ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/CALM_CHICK CALM_CHICK] Calmodulin mediates the control of a large number of enzymes, ion channels and other proteins by Ca(2+). Among the enzymes to be stimulated by the calmodulin-Ca(2+) complex are a number of protein kinases and phosphatases.
== 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/ah/1ahr_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=1ahr ConSurf].
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== Publication Abstract from PubMed ==
BACKGROUND: Calmodulin (CaM) is the major calcium-dependent regulator of a large variety of important intracellular processes in eukaryotes. The structure of CaM consists of two globular calcium-binding domains joined by a central 28-residue alpha helix. This linker helix has been hypothesized to act as a flexible tether and is crucial for the binding and activation of numerous target proteins. Although the way in which alterations of the central helix modulate the molecular recognition mechanism is not known exactly, the relative orientation of the globular domains seems to be of great importance. The structural analysis of central helix mutants may contribute to a better understanding of how changes in the conformation of CaM effect its function. RESULTS: We have determined the crystal structure of a calcium-saturated mutant of chicken CaM (mut-2) that lacks two residues in the central helix, Thr79 and Asp80, at 1.8 A resolution. The mutated shorter central helix is straight, relative to that of the wild-type structure. The loss of a partial turn of the central alpha helix causes the C-terminal domain to rotate 220 degrees around the helix axis, with respect to the N-terminal domain. This rotation places the two domains on the same side of the central helix, in a cis orientation, rather than in the trans orientation found in wild-type structures. CONCLUSIONS: The deletion of two residues in the central helix of CaM does not distort or cause a bending of the linker alpha helix. The main consequence of the mutation is a change in the relative orientation of the two globular calcium-binding domains, causing the hydrophobic patches in these domains to be closer and much less accessible to interact with the target enzymes. This may explain why this mutant of CaM shows a marked decrease in its ability to activate some enzymes while the mutation has little or no effect on its ability to activate others.

The structure of a calmodulin mutant with a deletion in the central helix: implications for molecular recognition and protein binding.,Tabernero L, Taylor DA, Chandross RJ, VanBerkum MF, Means AR, Quiocho FA, Sack JS Structure. 1997 May 15;5(5):613-22. PMID:9195880<ref>PMID:9195880</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 1ahr" style="background-color:#fffaf0;"></div>

==See Also==
*[[Calmodulin 3D structures|Calmodulin 3D structures]]
== References ==
<references/>
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</StructureSection>
[[Category: Gallus gallus]]
[[Category: Large Structures]]
[[Category: Sack J]]
[[Category: Tabernero L]]