6ANK

Synaptotagmin-7, C2A- and C2B-domains


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.25 Å
  • R-Value Free: 0.257 
  • R-Value Work: 0.214 
  • R-Value Observed: 0.218 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Exceptionally tight membrane-binding may explain the key role of the synaptotagmin-7 C2A domain in asynchronous neurotransmitter release.

Voleti, R.Tomchick, D.R.Sudhof, T.C.Rizo, J.

(2017) Proc Natl Acad Sci U S A 114: E8518-E8527

  • DOI: 10.1073/pnas.1710708114
  • Primary Citation of Related Structures:  
    6ANK, 6ANJ

  • PubMed Abstract: 
  • Synaptotagmins (Syts) act as Ca 2+ sensors in neurotransmitter release by virtue of Ca 2+ -binding to their two C 2 domains, but their mechanisms of action remain unclear. Puzzlingly, Ca 2+ -binding to the C 2 B domain appears to dominate Syt1 function in synchronous release, whereas Ca 2+ -binding to the C 2 A domain mediates Syt7 function in asynchronous release ...

    Synaptotagmins (Syts) act as Ca 2+ sensors in neurotransmitter release by virtue of Ca 2+ -binding to their two C 2 domains, but their mechanisms of action remain unclear. Puzzlingly, Ca 2+ -binding to the C 2 B domain appears to dominate Syt1 function in synchronous release, whereas Ca 2+ -binding to the C 2 A domain mediates Syt7 function in asynchronous release. Here we show that crystal structures of the Syt7 C 2 A domain and C 2 AB region, and analyses of intrinsic Ca 2+ -binding to the Syt7 C2 domains using isothermal titration calorimetry, did not reveal major differences that could explain functional differentiation between Syt7 and Syt1. However, using liposome titrations under Ca 2+ saturating conditions, we show that the Syt7 C 2 A domain has a very high membrane affinity and dominates phospholipid binding to Syt7 in the presence or absence of l-α-phosphatidylinositol 4,5-diphosphate (PIP 2 ). For Syt1, the two Ca 2+ -saturated C 2 domains have similar affinities for membranes lacking PIP 2 , but the C 2 B domain dominates binding to PIP 2 -containing membranes. Mutagenesis revealed that the dramatic differences in membrane affinity between the Syt1 and Syt7 C 2 A domains arise in part from apparently conservative residue substitutions, showing how striking biochemical and functional differences can result from the cumulative effects of subtle residue substitutions. Viewed together, our results suggest that membrane affinity may be a key determinant of the functions of Syt C 2 domains in neurotransmitter release.


    Related Citations: 
    • Structural and mutational analysis of functional differentiation between synaptotagmins-1 and -7.
      Xue, M., Craig, T.K., Shin, O.H., Li, L., Brautigam, C.A., Tomchick, D.R., Sudhof, T.C., Rosenmund, C., Rizo, J.
      (2010) PLoS One 5: --

    Organizational Affiliation

    Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Synaptotagmin-7A, B289Rattus norvegicusMutation(s): 0 
Gene Names: Syt7
Membrane Entity: Yes 
UniProt
Find proteins for Q62747 (Rattus norvegicus)
Explore Q62747 
Go to UniProtKB:  Q62747
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.25 Å
  • R-Value Free: 0.257 
  • R-Value Work: 0.214 
  • R-Value Observed: 0.218 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 60.637α = 90
b = 75.059β = 114.51
c = 70.98γ = 90
Software Package:
Software NamePurpose
HKL-3000data scaling
PHENIXrefinement
PDB_EXTRACTdata extraction
HKL-3000data reduction
PHASERphasing

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2017-09-20
    Type: Initial release
  • Version 1.1: 2017-10-04
    Changes: Database references
  • Version 1.2: 2017-11-08
    Changes: Database references