CaBP Data Library General Information

Information in the EF-Hand Calcium-Binding Proteins Database from Reference 48

Protein
 Species
 Information
 Comment
 Submitted By
 Validated By
calpain small subunit
small subunit
 Rattus norvegicus
(Norway rat)
 structure by x-ray crystallography (pdb entry 1AJ5) of homodimers of domain VI, thought to be representative of the domain IV-domain VI heterodimers
    		Melanie R. Nelson
    The Scripps Research Institute, Department of Molecular Biology
    mnelson@scripps.edu
    		 Melanie R. Nelson
    mnelson@scripps.edu
    calpain small subunit
    small subunit
    		 Rattus norvegicus
    (Norway rat)
    		 structure by x-ray crystallography (pdb entry 1DVI) of homodimers of domain VI, thought to be representative of the domain IV-domain VI heterodimers
    • bound to 3 ions of Ca
    		Melanie R. Nelson
    The Scripps Research Institute, Department of Molecular Biology
    mnelson@scripps.edu
    		 Melanie R. Nelson
    mnelson@scripps.edu
    calpain small subunit
    small subunit
    		 no species information The conformational change between apo and three calcium ions bound states involves:
    • The structuiral information available is for homodimers of domain VI from the small subunit of calpain. These homodimers are thought to mimic the biologically relevant heterodimers of domain VI with domain IV from the large subunit.
      The calcium-induced conformational changes in the homodimers of domain VI are relatively small. The largest changes are in EF-1, and in the positioning of the linker between EF1 and EF2, which moves closer to EF3/EF4 upon calcium binding.
    		 Calcium binds to EF-1, EF-2, and EF-3 at 1 mM Ca2+. At higher calcium concentrations (200 mM), a fourth calcium binds. This calcium binds atypically to the end of loop 4, and has eight oxygen ligands. It was displaced by yttterbium when the crystals were soaked with the heavy atom solution. There are no significant differences in the structures solved the low calcium and high calcium environment. The authors conlcude that this fourth binding site is unlikely to be occupied under physiological conditions.
    		 Melanie R. Nelson
    The Scripps Research Institute, Department of Molecular Biology
    mnelson@scripps.edu
    		 Melanie R. Nelson
    mnelson@scripps.edu