STING C-terminal Domain Complexed with Non-cyclic Dinucleotide Compound 11

Experimental Data Snapshot

  • Resolution: 1.93 Å
  • R-Value Free: 0.217 
  • R-Value Work: 0.189 
  • R-Value Observed: 0.191 

Starting Model: experimental
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Ligand Structure Quality Assessment 

This is version 1.2 of the entry. See complete history


An orally available non-nucleotide STING agonist with antitumor activity.

Pan, B.S.Perera, S.A.Piesvaux, J.A.Presland, J.P.Schroeder, G.K.Cumming, J.N.Trotter, B.W.Altman, M.D.Buevich, A.V.Cash, B.Cemerski, S.Chang, W.Chen, Y.Dandliker, P.J.Feng, G.Haidle, A.Henderson, T.Jewell, J.Kariv, I.Knemeyer, I.Kopinja, J.Lacey, B.M.Laskey, J.Lesburg, C.A.Liang, R.Long, B.J.Lu, M.Ma, Y.Minnihan, E.C.O'Donnell, G.Otte, R.Price, L.Rakhilina, L.Sauvagnat, B.Sharma, S.Tyagarajan, S.Woo, H.Wyss, D.F.Xu, S.Bennett, D.J.Addona, G.H.

(2020) Science 369

  • DOI: https://doi.org/10.1126/science.aba6098
  • Primary Citation of Related Structures:  
    6UKM, 6UKU, 6UKV, 6UKW, 6UKX, 6UKY, 6UKZ, 6UL0

  • PubMed Abstract: 

    Pharmacological activation of the STING (stimulator of interferon genes)-controlled innate immune pathway is a promising therapeutic strategy for cancer. Here we report the identification of MSA-2, an orally available non-nucleotide human STING agonist. In syngeneic mouse tumor models, subcutaneous and oral MSA-2 regimens were well tolerated and stimulated interferon-β secretion in tumors, induced tumor regression with durable antitumor immunity, and synergized with anti-PD-1 therapy. Experimental and theoretical analyses showed that MSA-2 exists as interconverting monomers and dimers in solution, but only dimers bind and activate STING. This model was validated by using synthetic covalent MSA-2 dimers, which were potent agonists. Cellular potency of MSA-2 increased upon extracellular acidification, which mimics the tumor microenvironment. These properties appear to underpin the favorable activity and tolerability profiles of effective systemic administration of MSA-2.

  • Organizational Affiliation

    Department of Quantitative Biosciences, Merck & Co., Inc., Kenilworth, NJ, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
fusion protein of Ubiquitin-like protein SMT3 and Stimulator of interferon protein c-terminal domain
A, B
300Saccharomyces cerevisiae S288CHomo sapiens
This entity is chimeric
Mutation(s): 2 
Gene Names: SMT3YDR510WD9719.15STINGLOC340061hCG_1782396
UniProt & NIH Common Fund Data Resources
Find proteins for Q12306 (Saccharomyces cerevisiae (strain ATCC 204508 / S288c))
Explore Q12306 
Go to UniProtKB:  Q12306
Find proteins for Q86WV6 (Homo sapiens)
Explore Q86WV6 
Go to UniProtKB:  Q86WV6
GTEx:  ENSG00000184584 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupsQ12306Q86WV6
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
QBA (Subject of Investigation/LOI)
Query on QBA

Download Ideal Coordinates CCD File 
C [auth A]4,4'-{propane-1,3-diylbis[oxy(5-methoxy-1-benzothiene-6,2-diyl)]}bis(4-oxobutanoic acid)
C29 H28 O10 S2
Experimental Data & Validation

Experimental Data

  • Resolution: 1.93 Å
  • R-Value Free: 0.217 
  • R-Value Work: 0.189 
  • R-Value Observed: 0.191 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 36.47α = 90
b = 109.29β = 95.5
c = 58.96γ = 90
Software Package:
Software NamePurpose
Aimlessdata scaling
PDB_EXTRACTdata extraction

Structure Validation

View Full Validation Report

Ligand Structure Quality Assessment 

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2020-08-19
    Type: Initial release
  • Version 1.1: 2020-09-02
    Changes: Database references
  • Version 1.2: 2023-10-11
    Changes: Data collection, Database references, Refinement description