NMR-driven secondary and tertiary structure model of Ca2+-loaded calexcitin.
Calexcitin (CE) is a Ca2+-binding protein which is expressed in neuronal cells and is a member of the sarcoplasmic Ca2+-binding protein subfamily. The peptide backbone of Ca2+-CE has been assigned by NMR and it shows that CE is composed of nine alpha-helices-forming four EF-hands and an additional helix near the C-terminus. A structural model of CE suggests the presence of a putative recessed hydrophobic pocket that may be involved in Ca2+-mediated protein-ligand interactions. This feature is unique to CE and is absent in other SCPs, such as those from Branchiostoma and Nereis, and from calerythrin.
Ontario Cancer Institute and Department of Medical Biophysics, University of Toronto, Ont., Canada M5G 1L7. zoltan.gombos@nrc-cnrc.gc.ca
Zoltan
Z
Gombos
Kyoko L
KL
Yap
Mitsuhiko
M
Ikura
Avijit
A
Chakrabartty
D001665:Binding Sites; D029742:Caenorhabditis elegans Proteins / Q000032:analysis / Q000737:chemistry*; D002118:Calcium / Q000032:analysis / Q000737:chemistry*; D002135:Calcium-Binding Proteins / Q000032:analysis / Q000737:chemistry*; D003198:Computer Simulation; D019204:GTP-Binding Proteins / Q000032:analysis / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008956:Models, Chemical; D008958:Models, Molecular; D011485:Protein Binding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary
D029742:Caenorhabditis elegans Proteins; D002135:Calcium-Binding Proteins; D019204:GTP-Binding Proteins; C102751:cex-2 protein, C elegans; D002118:Calcium