Amplified Luminescent Proximity Homogeneous Assay: A Bead-Based Proximity Assay to Screen Small Molecules Inhibiting Protein-Protein Interactions

Published: April 30, 2023

Abstract

Source: Wang, L. et al., Studies of Chaperone-Cochaperone Interactions using Homogenous Bead-Based Assay. J. Vis. Exp. (2021)

In this video, we demonstrate the amplified luminescent proximity homogeneous assay—a bead-based proximity assay. It utilizes homogeneously-sized acceptor and donor beads, immobilized with two proteins that tend to interact to screen potential small molecules inhibiting protein interactions.

Protocol

NOTE: An overview of this protocol is shown in Figure 1. 1. Expression and purification of GST-FKBP51 and GST-FKBP52 (Figure 1A) Plasmids NOTE: Obtain cDNA clones for human FKBP51 (clone id: 5723416) and for human FKBP52 (clone id: 7474554) from IMAGE consortium. Amplify the human FKBP51 DNA by PCR with primers (forward; 5`GGATCCATGACTACTGATGAAGGT-3`, reverse; 5`-CTCGAGCTATGCTTCTGTCTCCAC-3`) containing BamHI and …

Representative Results

Figure 1: Schematic of this protocol. (A) Expression and purification of GST-FKBP51 and GST-FKBP52. (B) Coupling of Hsp90 C-terminal peptide to the acceptor beads. (C) The assay probing the interaction between GST-FKBP51 or GST-FKBP52 and Hsp90 C-terminal peptide. Inhibition with small molecular mass compounds.

Declarações

The authors have nothing to disclose.

Materials

384-well plates Perkin Elmer 6008350 Assay volume 25 ml
Amicon 10.000 MWCO centrifugation unit Millipore UFC901008 Concentrate protein
Ampicillin Sigma A0166 Antibiotics
Bacteria shaker Unimax 1010 Heidolph Culture bacteria
cDNA clones for human FKBP51 Source BioScience clone id: 5723416 pCMV-SPORT6 vector
cDNA clones for human FKBP52 Source BioScience clone id: 7474554 pCMV-SPORT6 vector
Chemically Competent E. coli Invitrogen C602003 One Shot BL21 Star (DE3)
DMSO Supelco 1.02952.1000 Dilute compounds
DPBS Gibco 14190-144 Prepare solution
EDTA Calbiochem 344504 Prevent proteolysis during sonication
Glutathione Sigma G-4251 Elute GST-tagged proteins
Glutathione donor beads Perkin Elmer 6765300 Donor bead
GST-trap column Cytiva (GE Healthcare) 17528201 Purify GST-tagged proteins
Isopropyl-β-D-thiogalactoside Thermo Fisher Scientific R0392 Induce protein expression
LB Broth (Miller) Sigma L3522 Microbial growth medium
PCR instrument BIO-RAD S1000 Thermal Cycler Amplification/PCR
PD-10 column Cytiva (GE Healthcare) 17085101 Solution exchange
pGEX-6P-1 vector Cytiva (GE Healthcare) 28954648 Plasmid
pGEX-6P-2 vector Cytiva (GE Healthcare) 28954650 Plasmid
Plate reader Perkin Elmer EnSpire 2300 Multilabel Reader Read alpha plate
Plate reader software Perkin Elmer EnSpire Manager Plate reader software
Plate reader software protocol Perkin Elmer Alpha 384-well Low volume Use this protocol to read plate
PMSF Sigma P7626 Prevent proteolysis during sonication
protease inhibitor cocktail Sigma S8830 Prevent proteolysis during sonication
Sodium azide Sigma S2002 As a preservative
Sodium cyanoborohydride (NaBH3CN) Sigma 156159 Activates matrix for coupling
Ten amino acid peptide NH2-EDASRMEEVD-COOH corresponding to amino acids 714-724 of human Hsp90 beta isoform Peptide 2.0 inc Synthesize Hsp90 C-terminal peptide
Test-Tube Rotator LABINCO Make end-over-end agitation
Tris-HCl Sigma 10708976001 Block unreacted sites of acceptor beads
Tween-20 Sigma P1379 Prevent beads aggregation
Ultra centrifuge Avanti J-20 XP Beckman Coulter Centrifuge to get bacteria cell pellets
Ultrasonic cell disruptor Microson Sonicate cells to release protein
Unconjugated acceptor beads Perkin Elmer 6762003 Acceptor beads
XCell SureLock Mini-Cell and XCell II Blot Module Invitrogen EI0002 SDS-PAGE

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Amplified Luminescent Proximity Homogeneous Assay: A Bead-Based Proximity Assay to Screen Small Molecules Inhibiting Protein-Protein Interactions. J. Vis. Exp. (Pending Publication), e21231, doi: (2023).

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