BromoCatch^™ Platform

Self-labeling Proteins (SLPs) tag platform is the combination of a protein tag, expressed as a fusion to the protein-of-interest (POI), and a complementary small molecule ligand ('tag ligand') that potently (typically covalently) and selectively reacts with the protein tag (Figure 1). The key advantage of the technology is the intrinsic versatility of SLPs due to the small molecule ligand component, which can be modified to incorporate a wide variety of handles including fluorophores, biotin, click-chemistry handles, E3 ligase ligands for targeted degradation, and orthogonal domain-binding ligands for induced proximity applications.

Most popular self-labeling protein tags such as HaloTag^® and SNAP-tag^® can be fused to genes of interest to allow protein labeling in cells but present some limitations including size of the tag and suboptimal fitness of reactivity.

BromoCatch™, is a novel SLP platform based on a small ~13 kDa bromodomain (BD) engineered with a nucleophilic cysteine for covalent ligand engagement, allowing rapid, specific and stable protein labeling and multiplexed tag applications. This enables irreversible labeling of BromoCatch fusion protein in live cells, fixed cells, or lysates.

Figure 1. Self-labeling tag platforms for protein analysis and manipulation. A) Principle of self labeling tags. B) Current self-labeling protein tags and BromoCatch^™ description.

BromoCatch^™ Platform advantages

Minimal perturbation (less steric hindrance, less functional perturbation of the protein-of-interest)

Orthogonal SLP platform

One-construct with broad application range (fluorescent imaging, affinity pull down, bio-orthogonal chemistry, targeted degradation, bioconjugations, assay development)

Can be used for biochemical assays and live cell experiments

Suitable for FRET assays for studying protein-protein interactions

BromoCatch^™ Ligands

Discover our versatile BromoCatch™ Ligands for protein analysis and fixed cell and live cell imaging.

Cat. No.	Product Name	Activity	Emission Color	λex (nm)	λem (nm)	Application
8937	Janelia Fluor® 635 BromoCatch™ Ligand	Fluorescent covalent ligand for BromoCatch-tagged proteins	Far-red	635	652	No wash, live cell imaging
8940	BromoCatch™ Ligand, Alkyne	Clickable alkyne-functionalized covalent probe for BromoCatch-tagged proteins	-	-	-	Click chemistry
8939	Biotin BromoCatch™ Ligand	Biotinylated covalent ligand for BromoCatch-tagged proteins	-	-	-	Affinity pulldown and detection
7300	BromoCatch™ Control Ligand	Control ligand for use with BromoCatch	-	-	-	Negative control

Please see this protocol for further information on how to use our BromoCatch™ products.

BromoCatch is a trademark of Bio-Techne Corp.

Janelia Fluor is a registered trademark of Howard Hughes Medical Institute.

HaloTag is a trademark of Promega Corporation, and SNAP-tag is a trademark of New England BioLabs, Inc.

References

1. Baud et al.(2014) Chemical biology. A bump-and-hole approach to engineer-controlled selectivity of BET bromodomain chemical probes. Science 346 638. PMID:25323695
2. Runcie et al.(2018) Optimization of a "bump-and-hole" approach to allele-selective BET bromodomain inhibition. Chem.Sci. 9 2452. PMID: 29732121
3. Rodriguez-Rios et al. (2025) BromoCatch: a self-labelling tag platform for protein analysis and live cell imaging. biorxiv.