Structure of human Munc18-2

Experimental Data Snapshot

  • Resolution: 2.60 Å
  • R-Value Free: 0.275 
  • R-Value Work: 0.242 
  • R-Value Observed: 0.244 

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This is version 1.6 of the entry. See complete history


Syntaxin Binding Mechanism and Disease-Causing Mutations in Munc18-2

Hackmann, Y.Graham, S.C.Ehl, S.Hoening, S.Lehmberg, K.Arico, M.Owen, D.J.Griffiths, G.G.

(2013) Proc Natl Acad Sci U S A 110: E4482

  • DOI: https://doi.org/10.1073/pnas.1313474110
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Mutations in either syntaxin 11 (Stx11) or Munc18-2 abolish cytotoxic T lymphocytes (CTL) and natural killer cell (NK) cytotoxicity, and give rise to familial hemophagocytic lymphohistiocytosis (FHL4 or FHL5, respectively). Although Munc18-2 is known to interact with Stx11, little is known about the molecular mechanisms governing the specificity of this interaction or how in vitro IL-2 activation leads to compensation of CTL and NK cytotoxicity. To understand how mutations in Munc18-2 give rise to disease, we have solved the structure of human Munc18-2 at 2.6 Å resolution and mapped 18 point mutations. The four surface mutations identified (R39P, L130S, E132A, P334L) map exclusively to the predicted syntaxin and soluble N-ethylmaleimide-sensitive factor accessory protein receptor binding sites of Munc18-2. We find that Munc18-2 binds the N-terminal peptide of Stx11 with a ~20-fold higher affinity than Stx3, suggesting a potential role in selective binding. Upon IL-2 activation, levels of Stx3 are increased, favoring Munc18-2 binding when Stx11 is absent. Similarly, Munc18-1, expressed in IL-2-activated CTL, is capable of binding Stx11. These findings provide potential explanations for restoration of Munc18-Stx function and cytotoxicity in IL-2-activated cells.

  • Organizational Affiliation

    Cambridge Institute for Medical Research, University of Cambridge Biomedical Campus, University of Cambridge, Cambridge CB2 0XY, United Kingdom.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
SYNTAXIN-BINDING PROTEIN 2598Homo sapiensMutation(s): 0 
Gene Names: STXBP2UNC18B
UniProt & NIH Common Fund Data Resources
Find proteins for Q15833 (Homo sapiens)
Explore Q15833 
Go to UniProtKB:  Q15833
PHAROS:  Q15833
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ15833
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on CL

Download Ideal Coordinates CCD File 
Experimental Data & Validation

Experimental Data

  • Resolution: 2.60 Å
  • R-Value Free: 0.275 
  • R-Value Work: 0.242 
  • R-Value Observed: 0.244 
  • Space Group: P 41 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 67.55α = 90
b = 67.55β = 90
c = 284.651γ = 90
Software Package:
Software NamePurpose
MOSFLMdata reduction
Aimlessdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2013-10-30
    Type: Initial release
  • Version 1.1: 2013-11-06
    Changes: Atomic model, Other
  • Version 1.2: 2013-11-13
    Changes: Database references
  • Version 1.3: 2013-11-20
    Changes: Database references
  • Version 1.4: 2013-12-04
    Changes: Database references
  • Version 1.5: 2019-05-08
    Changes: Data collection, Experimental preparation, Other
  • Version 1.6: 2019-05-15
    Changes: Data collection, Experimental preparation