RU.521

Protein target name:

GAS

Mechanism of action:

Allosteric Inhibitor

Recommended Concentration for use in cells:

~~up to 1 uM~~

Reviewer suggested Concentration for use in cells:

up to 5 uM

Probe Availability

MedChemExpress

Probe Information

Target and Probe Information

Target Details

Target class:

Other

Define other target class:

Catalytic enzyme

Subclass:

cyclic GMP-AMP synthase

HUGO ID:

HGNC:21367

Entrez gene ID:

115004

UNIPROT ID:

Q8N884

Target alias:

MB21D1; h-cGAS; C6orf150

Probe Details

Chemical Probes Portal ID:

CPP2084

Probe alias:

RU320521, AEV

PubChem CID:

135397653

ChEMBL ID:

CHEMBL4567157

SMILES string:

O=C1OC(C2=C(O)N(C3=NC4=CC=C(Cl)C(Cl)=C4N3)N=C2C)C5=C1C=CC=C5

InChi Key:

IAWZUQAOMURCLV-UHFFFAOYSA-N

Physico-chemical properties

NMR:

1H NMR: (DMSO-d6, 400 MHz) δppm 7.83 (d, J = 7.7 Hz, 1 H), 7.75–7.67 (m, 1 H), 7.60–7.49 (m, 2 H), 7.42–7.35 (m, 1 H), 7.33–7.27 (m, 1 H), 6.58 (s, 1 H), 2.19 (br s, 3 H).

Validation in Cells and Model Organisms

In vitro validation

On target activity

Potency:

KD, IC50

36.2 nM (KD), 110 nM (IC50)

Potency assay:

ITC (KD), consumption of ATP and GTP, and the generation of cGAMP using an RF-MS

PDB ID for probe-target interaction (3D structure):

5XZG

Structure-activity relationship:

yes

In cell validation

On target activity in cells

Potency in cells:

IC50

700 nM

Potency assay (cells):

Small-molecule inhibition of cGAS-dependent interferon induction by double-strand DNA in cellular luciferase reporter assay

Off target activity in cells

Probe Selectivity in Cell:

RU.521 did not show any significant inhibition of reporter activity which is distinct from its activities in cells exposed to dsDNA when cGAS is present.

Toxicity

Cytoxicity assay:

Yes

Notes on cytotoxicity:

61.8 uM from CellTiter-Glo assay

Primary Reference

Reference (doi):

10.1038/s41467-017-00833-9

Reference (PMID):

28963528

Under Review

This probe is in the process of SAB review. Please continue to check back for new reviews and commentary.

SAB Rating

Rating for use in Cells

2 review(s)

Rating for use in Model Organisms

no rating

SAB Members

SAB Comments

The pursued screening hit possessed an acceptable structure but the remaining hits are questionable, including an electrophile and a PAINS compound. This could indicate that non-developable mechanisms of inhibition of possible with this protein. However, SAR investigation was largely focused on lipophilic substituents and did not include molecular matched pair analysis of polar contacts, so the specificity of binding is unclear. The kinetic analysis of the binding mode was performed with a weaker binding analogue of the proposed probe and appears to show a noncompetitive inhibition mechanism with both ATP and GTP (no change in Kmapp but clear decrease in kcat). This mechanism is not consistent with overlays of the inhibitor and substrates bound, which appear mutually exclusive, and could indicate some non-specific contribution to the biochemical inhibition. The small number of analogues tested, the lack of selectivity data, physicochemically matched negative controls and with no confirmed intracellular target engagement, means these compounds should be used with caution in cells.

Dec 8 2020 - 10:01am

RU.521

Probe Availability

Probe Information

Target Details

MB21D1; h-cGAS; C6orf150

Probe Details

Physico-chemical properties

In vitro validation

In cell validation

Toxicity

Primary Reference

Supporting Organizations

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RU.521

Probe Availability

Probe Information

Target Details

MB21D1; h-cGAS; C6orf150

Probe Details

Physico-chemical properties

In vitro validation

In cell validation

Toxicity

Primary Reference

Supporting Organizations

Interested in supporting the portal?