Download MendeleyStructure and ca(2+)-binding properties of the tandem c2 domains of e-syt2.
Xu, J., Bacaj, T., Zhou, A., Tomchick, D.R., Sudhof, T.C., Rizo, J.(2014) Structure 22: 269-280
- PubMed: 24373768
- DOI: https://doi.org/10.1016/j.str.2013.11.011
- Primary Citation of Related Structures:
4NPJ, 4NPK - PubMed Abstract:
Contacts between the endoplasmic reticulum and the plasma membrane involve extended synaptotagmins (E-Syts) in mammals or tricalbins in yeast, proteins with multiple C₂ domains. One of the tandem C₂ domains of E-Syt2 is predicted to bind Ca²⁺, but no Ca²⁺-dependent function has been attributed to this protein. We have determined the crystal structures of the tandem C₂ domains of E-Syt2 in the absence and presence of Ca²⁺ and analyzed their Ca²⁺-binding properties by nuclear magnetic resonance spectroscopy. Our data reveal an unexpected V-shaped structure with a rigid orientation between the two C₂ domains that is not substantially altered by Ca²⁺. The E-Syt2 C2A domain binds up to four Ca²⁺ ions, whereas the C₂B domain does not bind Ca²⁺. These results suggest that E-Syt2 performs an as yet unidentified Ca²⁺-dependent function through its C₂A domain and uncover fundamental differences between the properties of the tandem C₂ domains of E-Syts and synaptotagmins.
Organizational Affiliation:
Department of Biophysics, University of Texas Southwestern Medical Center, 6000 Harry Hines Boulevard, Dallas, TX 75390, USA; Department of Biochemistry, University of Texas Southwestern Medical Center, 6000 Harry Hines Boulevard, Dallas, TX 75390, USA; Department of Pharmacology, University of Texas Southwestern Medical Center, 6000 Harry Hines Boulevard, Dallas, TX 75390, USA.
