Protein Interaction Analysis Service

What Is Protein Interaction Analysis?

Protein interactions refer to physical or functional associations between proteins and other biomolecules, including proteins, DNA, RNA, peptides, and small molecules.

 

These interactions influence signaling, molecular complex formation, gene regulation, RNA processing, and other cellular processes. Protein interaction analysis helps identify candidate interaction partners, characterize molecular complexes, and investigate how specific interactions change in response to biological conditions or experimental perturbations.

 

Figure 1. Schematic of Interaction of Proteins with Biological Molecules

Service Category

MtoZ Biolabs provides integrated interaction analysis strategies covering interaction discovery, protein-nucleic acid analysis, binding affinity measurement, and structural characterization. The analytical approach is selected according to the target system and study objective.

1. Protein-Protein Interaction Discovery and Complex Profiling

MtoZ Biolabs provides Co-IP/Co-IP-MS, Pull-Down/Pull-Down-MS, Affinity Purification-MS (AP-MS), and Proximity Labeling-MS for protein interaction discovery and complex profiling.

Co-IP/Co-IP-MS is used to analyze proteins associated with endogenous target-containing complexes. Pull-Down-MS supports affinity-based screening using purified or tagged bait proteins. AP-MS is suited to profiling complexes associated with affinity-tagged targets. For weak, transient, or spatially restricted associations, Proximity Labeling-MS offers an alternative strategy for profiling proteins within the local environment of a target.

 

2. Protein-Nucleic Acid Interaction Analysis

Protein-DNA and protein-RNA interactions can be analyzed from either the nucleic acid or protein side. 

DNA Pull-Down MS and RNA Pull-Down MS are used to identify proteins associated with defined DNA or RNA sequences. RNA Immunoprecipitation (RIP) supports analysis of RNAs associated with a target RNA-binding protein, while ChIRP-MS/ChIRP-Seq is available for chromatin-associated RNA studies. For genome-wide protein-chromatin profiling, ChIP-Seq and CUT&Tag are available according to sample type and project requirements.

 

3. Binding Affinity and Interaction Validation

For predefined interaction pairs, MtoZ Biolabs provides Surface Plasmon Resonance (SPR), Biolayer Interferometry (BLI), and Microscale Thermophoresis (MST).

These platforms support affinity characterization of protein-protein, protein-peptide, protein-nucleic acid, and protein-small molecule interactions. Depending on the selected method, results may include equilibrium binding affinity and association or dissociation parameters.

 

4. Structural and Conformational Interaction Analysis

For projects requiring structural information beyond interaction partner identification, MtoZ Biolabs provides Cross-Linking Mass Spectrometry (XL-MS) and Hydrogen-Deuterium Exchange Mass Spectrometry (HDX-MS).

XL-MS provides crosslink-site information and spatial constraints within proteins and protein complexes. HDX-MS monitors changes in protein dynamics and solvent accessibility at the peptide level and is suited to protein-protein, protein-ligand, and antibody-antigen interaction studies.

Choose the Right Protein Interaction Workflow

Research Question	Recommended Direction
Which proteins associate with my target in a native complex?	Co-IP-MS
Which proteins associate with an affinity-tagged target?	AP-MS
Which proteins bind a purified bait in vitro?	Pull-Down-MS
Which proteins are transiently or spatially associated with my target?	Proximity Labeling-MS
Which proteins associate with a defined DNA or RNA sequence?	DNA Pull-Down MS, RNA Pull-Down MS
Where does a target protein associate with chromatin?	ChIP-Seq, CUT&Tag
How strong is a defined molecular interaction?	SPR, BLI, MST
What spatial constraints exist within a protein complex?	XL-MS
How does binding affect protein conformation?	HDX-MS

Analysis Workflow

1. Project Evaluation

Target information, biological system, interaction type, available reagents, comparison design, and project objectives are reviewed before workflow selection.

 

2. Strategy Selection

The analytical approach is selected according to whether the project focuses on interaction discovery, complex profiling, nucleic acid interactions, affinity measurement, or structural characterization.

 

3. Interaction Analysis

Samples are processed using the selected enrichment, proximity, crosslinking, nucleic acid capture, or biophysical workflow. MS-based projects use high-resolution mass spectrometry for protein, peptide, or crosslinked peptide analysis.

 

4. Data Analysis

Results are processed according to the selected platform and may include interaction partner identification, protein complex profiles, proximity profiles, binding parameters, crosslink sites, or conformational changes.

 

Service Advantages

1. Advanced Interaction Analysis Platform

Mass spectrometry, affinity enrichment, nucleic acid interaction, biophysical, and structural MS platforms support a broad range of protein interaction studies.

 

2. High-Resolution MS Capabilities

High-resolution mass spectrometry supports protein identification, interaction partner profiling, crosslinked peptide analysis, and downstream quantitative comparison when applicable.

 

3. Integrated Interaction Characterization

Interaction discovery can be followed by affinity or structural characterization for selected candidate pairs.

 

4. Project-Specific Workflow Design

Workflow selection is based on the biological system, target characteristics, available reagents, interaction type, and research objective.

 

5. One-Time Charge

Our pricing is transparent, with no hidden fees or additional costs.

Sample Submission Suggestions

Sample types vary by interaction strategy and may include:

• Cells and cell lysates
• Animal or plant tissues
• Microbial samples
• Body fluids where applicable
• Purified or recombinant proteins
• Peptides, nucleic acids, or small molecules for defined binding studies
• IP/Pull-Down beads, eluates, gel bands, or protein solutions
• Affinity-tagged or labeled biological samples

Recommended sample amount, preparation, storage, and shipping conditions depend on the selected method. Contact us with your sample type and study goal for project-specific recommendations.

Applications

1. Disease Mechanism Research

Characterization of disease-associated protein complexes, interaction partners, and altered molecular networks.

 

2. Drug Discovery and Development

Target characterization, interaction validation, protein-ligand binding analysis, mechanism-of-action studies, and structural characterization of molecular interactions.

 

3. Cell Signaling Research

Analysis of signaling complexes, regulatory proteins, and interaction changes associated with cellular signaling pathways.

 

4. Protein Function Research

Identification of interaction partners and protein complexes to support functional characterization of target proteins.

 

5. Gene and RNA Regulation

Analysis of protein-DNA, protein-RNA, chromatin-associated, and RNA-binding interactions involved in gene and post-transcriptional regulation.

Deliverables

Deliverables are defined according to the selected workflow and may include:

1. Experimental Details

Study design and workflow information.

2. Methods and Parameters

Key experimental and analytical settings.

3. Analysis Results

Interaction partners, protein complexes, nucleic acid interactions, binding affinity, crosslink sites, or conformational analysis results according to the selected workflow.

4. Processed Data

Identification tables, quantitative data, and visualization results.

5. Raw Data and Report

Raw analytical files and project report.

Case Study

1. Protein Interaction Mapping by Cross-Linking Mass Spectrometry

Lenz et al. applied XL-MS to large-scale protein interaction mapping in Escherichia coli and constructed a protein-protein interaction network using controlled false discovery rate estimation.

 

Crosslinked peptide information also provided spatial constraints for protein complexes, demonstrating the ability of XL-MS to combine interaction mapping with structural information.

Lenz S. et al. Nature Communications. 2021.

Figure 2. Crosslinking MS-Derived Protein-Protein Interaction Network of the E. coli Proteome

2. Proximity-Based Interaction Profiling of EGFR

Yamada et al. used proximity biotinylation followed by LC-MS/MS to profile proteins located near extracellular EGFR. The study compared proximity profiles under EGF stimulation and gefitinib treatment, demonstrating the application of proximity-based proteomics to dynamic extracellular protein environments.

Yamada K. et al. Nature Communications. 2023.

Figure 3. Protein-Protein Interaction Analysis Targeting EGFR

FAQ

Q1: Can you support projects when the interaction partner is unknown?

Yes. Discovery workflows such as Co-IP-MS, Pull-Down-MS, AP-MS, and Proximity Labeling-MS can be used to identify candidate interaction partners or protein complexes before targeted follow-up.

 

Q2: Can discovery and validation be combined in the same project?

Yes. Candidate interactors identified by MS-based discovery can be followed with affinity or structural characterization using SPR, BLI, MST, XL-MS, or HDX-MS when appropriate.

 

Q3: What information is needed before starting a protein interaction project?

Please provide the target protein, biological system, available samples or reagents, known interaction information if available, and the primary research objective. These details are used to select the most appropriate workflow.

 

Contact Us

Share your target protein, biological system, interaction type, available materials, and research objective with MtoZ Biolabs.

Our technical team will help select an appropriate workflow for interaction discovery, validation, binding characterization, or structural analysis.