1a8y

<StructureSection load='1a8y' size='340' side='right' caption='[[1a8y]], [[Resolution|resolution]] 2.40&Aring;' scene=''>

<table><tr><td colspan='2'>[[1a8y]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Oryctolagus_cuniculus Oryctolagus cuniculus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1A8Y OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1A8Y FirstGlance]. <br>

</td></tr><tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1a8y FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1a8y OCA], [http://pdbe.org/1a8y PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1a8y RCSB], [http://www.ebi.ac.uk/pdbsum/1a8y PDBsum]</span></td></tr>

[[http://www.uniprot.org/uniprot/CASQ1_RABIT CASQ1_RABIT]] Calsequestrin is a high-capacity, moderate affinity, calcium-binding protein and thus acts as an internal calcium store in muscle. The release of calcium bound to calsequestrin through a calcium release channel triggers muscle contraction. The skeletal muscle isoform (CASQ1) binds around 80 Ca(2+) ions, while the cardiac isoform (CASQ2) binds approximately 60 Ca(2+) ions (By similarity).

<scriptWhenChecked>select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/a8/1a8y_consurf.spt"</scriptWhenChecked>

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== Publication Abstract from PubMed ==

Calsequestrin, the major Ca2+ storage protein of muscle, coordinately binds and releases 40-50 Ca2+ ions per molecule for each contraction-relaxation cycle by an uncertain mechanism. We have determined the structure of rabbit skeletal muscle calsequestrin. Three very negative thioredoxin-like domains surround a hydrophilic center. Each monomer makes two extensive dimerization contacts, both of which involve the approach of many negative groups. This structure suggests a mechanism by which calsequestrin may achieve high capacity Ca2+ binding. The suggested mechanism involves Ca2+-induced collapse of the three domains and polymerization of calsequestrin monomers arising from three factors: N-terminal arm exchange, helix-helix contacts and Ca2+ cross bridges. This proposed structure-based mechanism accounts for the observed coupling of high capacity Ca2+ binding with protein precipitation.

Crystal structure of calsequestrin from rabbit skeletal muscle sarcoplasmic reticulum.,Wang S, Trumble WR, Liao H, Wesson CR, Dunker AK, Kang CH Nat Struct Biol. 1998 Jun;5(6):476-83. PMID:9628486<ref>PMID:9628486</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

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== References ==

<references/>

[[Category: Dunker, A K]]

[[Category: Kang, C]]

[[Category: Liao, H]]

[[Category: Trumble, W R]]

[[Category: Wang, S]]

[[Category: Wesson, C R]]

[[Category: Sarcoplasmic reticulum]]