KRAS(G12D) Coupled Nucleotide Exchange Assay Kit

Catalog #
78570
$1,355 *
Size: 384 reactions
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Description

The KRAS(G12D) Coupled Nucleotide Exchange Assay Kit is designed for screening and profiling of KRAS(G12D) antagonists/inhibitors by monitoring the binding of an effector protein such as the Ras binding domain of Raf1, (RBD-cRaf) to KRAS(G12D). The KRAS(G12D) Coupled Nucleotide Exchange Assay Kit comes in a convenient 384-well format, with enough purified recombinant GDP-loaded KRAS(G12D) Isoform A, GTP, exchange factor SOS1 (amino acids 564-1049), effector protein RBD-cRAF (amino acids 50-140), assay buffer and additives for 400 reactions. With this kit, a few simple steps on a microtiter plate are required for nucleotide exchange detection. First, a sample containing GDP-loaded KRAS(G12D) is incubated with SOS1 and GTP for the nucleotide exchange. Next, RBD-cRAF is added and incubated for the effector-RAS binding. Then, acceptor and donor beads are added and incubated for detection followed by reading the Alpha-counts.

SOS1 (son of sevenless) is a guanine nucleotide exchange factor that facilitates the exchange of GDP for GTP. GDP-loaded KRAS(G12D) is in an inactive state and does not interact with the Ras-binding domain (RBD) of cRAF.  SOS1 assists in the release of GDP from KRAS(G12D) so that GTP can occupy the nucleotide binding pocket. This results in a conformational change in KRAS(G12D) that permits its binding to RBD-cRAF. The KRAS(G12D) Coupled Nucleotide Exchange Assay Kit utilizes GST-tagged RBD-cRAF and His-tagged KRAS (G12D) to assay binding of KRAS(G12D) to RBD-cRAF in the Alpha assay. Glutathione acceptor and Ni chelate donor beads are brought into proximal range by the binding of KRAS(G12D) and RBD-cRAF, enabling the energy transfer from the donor to acceptor beads after laser excitation. 

KRAS(G12D) Coupled Nucleotide Exchange Assay Kit

Figure 1: Illustration of the assay principle.

Product Info
Storage and Usage
Citations
Assay Kit Format
AlphaLISA®
Materials Required But Not Supplied
Name Ordering Information
AlphaLISA® Glutathione acceptor beads, 5 mg/ml PerkinElmer #AL109C
AlphaScreen® Nickel Chelate donor beads, 5 mg/ml PerkinElmer #AS101D
Optiplate -384 PerkinElmer #6007290
AlphaScreen® microplate reader  
Adjustable micropipettor and sterile tips  
Format
Catalog # Name Amount Storage
101312 KRAS(G12D), Isoform A, His-Tag, GDP-Loaded * 5 µg -80°C
101573 SOS1, FLAG-Tag* 50 µg -80°C
100519 RBD-cRAF, GST-Tag* 5 µg -80°C
79861-2 10 mM GTP 0.5 ml -20°C
  RBD-RAS Binding Buffer (Incomplete) 2 x 3 ml -20°C
  0.5 M DTT 2 x 200 µl -20°C
79311 3x Immuno Buffer 1 4 ml -20°C

*The concentration of the protein is lot-specific and will be indicated on the tube.

UniProt #
P01116
Background

It is well established that RAS mutations are responsible for more than 30% of human cancers. KRAS(G12D) is the most common mutation (33%) among KRAS mutant tumors. The G12D mutation favors the activated (GTP-bound) state of KRAS, amplifying signaling pathways that lead to oncogenesis. Recent studies have led to the discovery of a small molecule called MRTX1133 (Mirati) that locks KRAS conformation in the GDP-bound inactive state, thereby blocking KRAS(G12D)-mediated signaling pathway.  Compounds that affect the nucleotide exchange (GDP to GTP) reaction could lead to a novel approach leading to the inhibition of tumor cell growth in KRAS(G12D) driven tumors.

References

Wang, X., et al., 2022 J Med Chem 65: 3123-33.
Hillig, R.C., et al., 2019 PNAS USA 116 (7): 2551-2560