4NPK

Extended-Synaptotagmin 2, C2A- and C2B-domains, calcium bound

Summary for 4NPK

• Entry DOI: 10.2210/pdb4npk/pdb
• Related: 4NPJ
• Descriptor: Extended synaptotagmin-2, CALCIUM ION (3 entities in total)
• Functional Keywords: calcium/phospholipid binding protein, c2 domain, er to plasma membrane, membrane traffic, protein targeting, plasma membrane, membrane protein
• Biological source: Homo sapiens (human)
• Cellular location: Cell membrane; Peripheral membrane protein: A0FGR8
• Total number of polymer chains: 1
• Total formula weight: 34385.35

Authors

Tomchick, D.R.,Rizo, J.,Xu, J. (deposition date: 2013-11-21, release date: 2014-01-29, Last modification date: 2023-09-20)

Primary citation

Xu, J.,Bacaj, T.,Zhou, A.,Tomchick, D.R.,Sudhof, T.C.,Rizo, J.
Structure and ca(2+)-binding properties of the tandem c2 domains of e-syt2.
Structure, 22:269-280, 2014

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.

PubMed: 24373768
DOI: 10.1016/j.str.2013.11.011

Experimental method

X-RAY DIFFRACTION (2.552 Å)