Crystal structure of calpain‐3 penta‐EF‐hand (PEF) domain – a homodimerized PEF family member with calcium bound at the fifth EF‐hand. (9th June 2014)

• Record Type: Journal Article
• Authors: Partha, Sarathy K.; Ravulapalli, Ravikiran; Allingham, John S.; Campbell, Robert L.; Davies, Peter L.
• Is Part Of: FEBS journal. Volume 281:Number 14(2014)
• Page Start: 3138
• Page End: 3149
• Publication Date: 2014-06-09
• Subjects: Biochemistry -- Periodicals; Molecular biology -- Periodicals; Pathology, Molecular -- Periodicals; 572
• DOI: 10.1111/febs.12849
• Languages: English
• ISSNs: 1742-464X

Abstract

<abstract abstract-type="main" id="febs12849-abs-0001"> <title> <x xml:space="preserve">Abstract</x> </title> <sec id="febs12849-sec-0001" sec-type="section"> <p>Calpains are Ca<sup>2+</sup>dependent intracellular cysteine proteases that cleave a wide range of protein substrates to help implement Ca<sup>2+</sup> signaling in the cell. The major isoforms of this enzyme family, calpain‐1 and calpain‐2, are heterodimers of a large and a small subunit, with the main dimer interface being formed through their C‐terminal penta‐EF hand (PEF) domains. Calpain‐3, or p94, is a skeletal muscle‐specific isoform that is genetically linked to limb‐girdle muscular dystrophy. Biophysical and modeling studies with the PEF domain of calpain‐3 support the suggestion that full‐length calpain‐3 exists as a homodimer. Here, we report the crystallization of calpain‐3′s PEF domain and its crystal structure in the presence of Ca<sup>2+</sup>, which provides evidence for the homodimer architecture of calpain‐3 and supports the molecular model that places a protease core at either end of the elongated dimer. Unlike other calpain PEF domain structures, the calpain‐3 PEF domain contains a Ca<sup>2+</sup> bound at the EF5‐hand used for homodimer association. Three of the four Ca<sup>2+</sup>‐binding EF‐hands of the PEF domains are concentrated near the protease core, and have the potential to radically change the local charge within the dimer during Ca<sup>2+</sup> signaling. Examination of the homodimer interface shows that there would be steric clashes if the calpain‐3 large subunit were to try to pair with a calpain small subunit.</p> <sec id="febs12849-sec-0002" sec-type="section"> <title>Database</title> <p>Structural data are available in the Protein Data Bank database under accession number <ext-link ext-link-type="uri" xlink:href="http://www.rcsb.org/pdb/search/structidSearch.do?structureId=4OKH" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink">4OKH</ext-link>.</p> </sec> </sec> <sec id="febs12849-sec-0003" sec-type="section"> <title>Structured digital abstract</title> <p> <ext-link ext-link-type="uri" xlink:href="http://www.uniprot.org/uniprot/P20807" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink">Calpain-3</ext-link> and <ext-link ext-link-type="uri" xlink:href="http://www.uniprot.org/uniprot/P20807" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink">Calpain-3</ext-link> <ext-link ext-link-type="uri" xlink:href="http://www.ebi.ac.uk/ontology-lookup/?termId=MI:0407" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink">bind</ext-link> by <ext-link ext-link-type="uri" xlink:href="http://www.ebi.ac.uk/ontology-lookup/?termId=MI:0114" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink">x-ray crystallography</ext-link> (<ext-link ext-link-type="uri" xlink:href="http://www.ebi.ac.uk/intact/interaction/EBI-9525089" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink">View interaction</ext-link>)</p> </sec> </abstract>