Custom multi-pass transmembrane proteins displayed on VLPs or nanodiscs
Challenges of Transmembrane Proteins in Drug Development
Transmembrane proteins (TPs) are crucial for various physiological processes, including protein ligation, recognition, transport, anchoring, and signal transduction. Abnormalities in transmembrane proteins are linked to numerous diseases, making them vital targets for drug development, with about 50% of drugs targeting these proteins. However, the complex structure of multi-pass transmembrane proteins, characterized by multiple hydrophobic transmembrane regions and low expression levels in host cells, poses significant challenges for their purification and use in drug development. For effective therapeutic targeting, it is essential to isolate full-length, biologically relevant transmembrane proteins with native folding to fully characterize antibody activity and mechanisms of action. Despite their challenges, these highly sought-after disease targets demand advanced solutions to overcome low expression, in vitro insolubility, and unstable purification while maintaining their natural conformation.
Custom solutions for full-length transmembrane protein expression
KACTUS offers innovative solutions for studying membrane proteins by displaying multi-transmembrane proteins on Virus-Like Particles (VLPs) or nanodiscs. These platforms provide a stable and controlled environment, enabling detailed analysis of protein structure, function, and interactions. This approach drives advancements in drug discovery, immunization, and diagnostic assays.We have developed a comprehensive catalog of full-length multi-pass transmembrane proteins with stabilized structure and high activity, including CD20, Claudin 18.2, GPRC5D, CXCR4, CCR5, and CCR8. Additionally, we offer custom transmembrane protein expression on VLPs or nanodiscs.
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Service Overview
Product Formats
Virus-like-particle (VLP):
We have developed a robust system for expressing transmembrane proteins on Virus-like Particles (VLPs), enhancing their utility for various research and therapeutic purposes. VLPs have versatile applications, including immunization and antibody drug discovery, phage display screening, yeast display screening, PK/PD studies, and analytical tests such as ELISA and SPR/BLI. Additionally, our team can customize your VLP to meet your experimental requirements, including immunization guides, in vivo biotinylation, fluorescent labeling, and FACS-compatible VLPs.
Nanodisc:
Our copolymer nanodisc expression platform can display multi-pass transmembrane proteins with detergent-free extraction, providing a versatile tool for various research applications. Nanodiscs are utilized in yeast display screening, in vitro functional assays, PK/PD studies, and analytical tests such as ELISA and SPR/BLI. Additionally, we can customize the nanodisc for your research, including in vivo biotinylation, and fluorescent labeling.
Service Features
6 weeks turnaround time
HEK293 Expression
Full-Length Protein
Customized Proteins
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Areas of Expertise
We have successfully expressed a variety of full-length transmembrane proteins using our VLP & Nanodisc multi-transmembrane protein expression systems. Our expertise includes:
GPCRs
G-protein-coupled receptors (GPCRs) are a diverse group of membrane receptors that detect molecules outside the cell and activate internal signal transduction pathways and cellular responses.
Successfully Expressed:
- CCR2b
- CCR4
- CCR5
- CCR6
- CCR7
- CCR8
- CB1
- CB2
- CXCR4
- GPR75
- GPR77
- GLP-1R
- GPRC5D
- A2AR
- BILF1
- MRGPRX2
- SSTR2
- GCGR
Solute Carriers
Solute carrier (SLC) proteins are a large family of membrane transport proteins that play critical roles in transporting a wide variety of substrates across cellular membranes.
Successfully Expressed:
- SLC1A4
- SLC1A5
- SLC7A1
- SLC15A4
- SLC13A5
- SLC16A1
- SLC16A3
- SLC34A2
- SLC40A1
- SLC44A4
- SLC59A1
4HB/Tetraspanins
Four-helix bundle (4HB) proteins are structural motifs in proteins in which four alpha helices are arranged in a bundle along with two extracellular domains. These proteins are involved in various cellular processes, including signaling and transport.
Successfully Expressed:
- Claudin 1
- Claudin 3
- Claudin 6
- Claudin 9
- Claudin 18.2
- CD20
- TM4SF1
Don't see your protein listed? We love a challenge!
Let us know what difficult-to-express protein you're interested in and we'll let you know the feasibility.
Case Studies
We have validated via various assays the performance of our custom VLP and nanodisc-displayed transmembrane proteins. This includes dynamic light scattering, SPR, BLI, flow cytometry, ELISA, and HPLC. Our expertise in recombinant protein production ensures high-quality, and bioactive protein solutions for drug discovery.
Claudin 18.2 VLP
KACTUS was the first company to product full-length Claudin 18.2, a challenging drug discovery target with four transmembrane domains. Claudin 18.2, a tight junction protein, plays a crucial role in cellular adhesion and barrier function. We developed multiple variations of Claudin 18.2 VLPs including biotinylated, non-biotinylated, and fluorescent-labeled forms, providing researchers with versatile options to suit various experimental needs.
Figure 1. ELISA assay shows the binding activity of Claudin 18.2 VLPs to anti-Claudin 18.2 antibodies across three different production batches. The consistent curves for Batches 1, 2, and 3 highlight the reproducibility and stability of the VLP preparations. The half-maximal effective concentration (EC50) is determined to be 0.1 nM, indicating high affinity and robust interaction between Claudin 18.2 VLPs and the specific antibodies.
Figure 2. SPR data showing the binding interactions of Biotinylated Claudin 18.2 VLPs with streptavidin immobilized on a CM5 chip. Results show a dissociation constant (KD) of 1.638E-11 M. This indicates a very strong and stable binding affinity of the Claudin 18.2 VLP.
CXCR4 VLP
Our team has expressed full-length CXCR4, a complex GPCR protein characterized by its seven transmembrane domains. CXCR4 is a G protein-coupled receptor that plays a crucial role in immune cell migration and is implicated in cancer metastasis, HIV infection, and stem cell mobilization. We have expressed full-length CXCR4 VLPs and Nanodiscs, validated via FACS, providing researchers with versatile options to meet diverse experimental requirements.
Figure 3. Flow Cytometry Analysis of CXCR4 VLPs with Anti-CXCR4 Antibodies (Red and Green). The top row displays control samples without the anti-CXCR4 antibody, showing minimal binding and low background signal in both APC and FITC channels. The bottom row shows samples treated with anti-CXCR4 antibodies (red and green), revealing significant shifts in fluorescence intensity indicating specific binding of the antibodies to CXCR4 VLPs, emphasizing the effective recognition and binding of the anti-CXCR4 antibody to the CXCR4 VLPs.
SLC13A5 Nanodisc
KACTUS has successfully developed full-length SLC13A5, a challenging drug discovery target known for its six transmembrane domains. SLC13A5, a sodium-coupled citrate transporter, plays a vital role in cellular metabolism and energy production. We have created an SLC13A5 copolymer nanodisc with detergent-free extraction.
Figure 4. Full-length SLC13A5 nanodisc was tested using BLI. The His-tagged SLC13A5 nanodisc was immobilized on an Anti-His chip, and the binding interaction was analyzed using the 11H7B8 antibody at varying concentrations: 1023.33, 511.67, 255.83, 127.92, 63.96, 31.98, and 15.99 nM. The KD value of 28.4 nM indicates a high affinity of the SLC13A5 nanodisc for the 11H7B8 antibody.
Figure 5. Dynamic Light Scattering (DLS) Analysis of Human SLC13A5 Nanodiscs. The peak is centered around a radius of 13.96 nm, with a corresponding intensity of 21.89%, suggesting that the Human SLC13A5 nanodiscs are predominantly monodisperse, with minimal aggregation.
GPRC5D Nanodisc
We have successfully developed full-length GPRC5D, a popular drug discovery target with seven transmembrane domains. GPRC5D, an orphan G protein-coupled receptor, is implicated in various cellular signaling pathways. We have developed various GPRC5D products including VLPs and nanodiscs, biotinylated versions, and other species (cynomolgus, mouse).
Figure 6. Human GPRC5D Nanodisc, His Tag captured on CM5 Chip via anti-his antibody can bind Anti-GPRC5D Antibody with an affinity constant of 1.47 nM as determined in SPR assay (Biacore T200).
Figure 7. The binding interaction of Anti-GPRC5D Antibody with Biotinylated Human GPRC5D Nanodisc was analyzed using BLI. The nanodisc was immobilized using a streptavidin (SA) biosensor. The KD value of of 1.16 nM indicates a high affinity for the Anti-GPRC5D antibody.
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Solute Carrier Proteins
Request a custom solute carrier protein expressed on a VLP or Nanodisc
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SPR Analysis Services
Surface plasmon resonance analysis of various sample combinations including antibodies and proteins
catalog products
VLPs & Nanodiscs
Browse our in-stock catalog selection of VLP & Nanodisc transmembrane proteins
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60 Hickory Drive
Waltham, MA 02451
United States
Custom VLP or Nanodisc Target Antigen