mRNA Display Technology
mRNA display technology is one of the highest-capacity in vitro screening platforms in biopharmaceutical discovery. It overcomes the library size limitations and cell-dependent constraints of traditional display methods, such as phage display, by employing a cell-free in vitro translation system that establishes a covalent physical linkage between the mRNA (genotype) and its encoded peptide/protein (phenotype). This linkage—often referred to as the "phenotype-to-genotype connection"—enables the screening of ultra-large libraries containing up to 1014 unique sequences, allowing for the efficient identification of high-affinity, high-specificity hit molecules even against challenging targets that are refractory to conventional approaches, including GPCRs and KRAS. The technology is broadly applicable across a range of frontier research areas, including peptide drug discovery, antibody development, protein-protein interaction studies, and targeted ligand mining.
MCE offers cyclic peptide mRNA display libraries (Table 1) based on the CXnC framework, in which two fixed cysteine residues flank a randomized region. Post‑translation, the side‑chain thiols are chemically crosslinked to lock the random region into a monocyclic rigid conformation, enhancing target affinity by reducing the entropic penalty and improving metabolic stability and membrane permeability. The libraries span ring sizes from CX8C to CX14C, with theoretical diversities ranging from 1010 to 1014. The X3CX8CX3 library features a cyclic core flanked by dual flexible arms, combining rigidity with binding adaptability—ideal for challenging targets such as GPCRs. These libraries support diverse applications, from epitope scanning to high‑affinity binder discovery against complex protein surfaces.
Table 1. MCE mRNA Display Libraries
| Name | Type | Size | |
|---|---|---|---|
 |
CX8C | Monocyclic peptide (8 random amino acids) | 1010 |
 |
CX10C | Monocyclic peptide (10 random amino acids) | 1013 |
 |
CX12C | Monocyclic peptide (12 random amino acids) | 1014 |
 |
CX14C | Monocyclic peptide (14 random amino acids) | 1014 |
 |
X3CX8CX3 | Monocyclic peptide with dual flexible arms (14 random amino acids) | 1014 |
mRNA Display Library Construction and Screening
The elegance of mRNA display lies in "puromycin bridging". Puromycin is ligated to the 3' end of mRNA. When the ribosome reaches the end of translation, puromycin mimics tyrosine, enters the ribosomal A-site, and forms an irreversible covalent amide bond with the C-terminus of the nascent peptide. This covalent coupling ensures traceability between the "input" and "output" of each selection round—effectively reducing background noise while allowing even weak-affinity binders to be captured and progressively enriched.
Following incubation of the library with the immobilized target protein, specifically bound peptide-mRNA fusions are captured and eluted. The selection information (mRNA) is then reverse-transcribed into cDNA via RT-PCR and amplified to drive the next round of selection. Through several rounds of this "bind-wash-amplify" cycle, high-affinity binders are progressively enriched while non‑binders are depleted. The final-round pool is subjected to NGS, and bioinformatics analysis (enrichment fold, sequence clustering) decodes high-confidence candidate peptide sequences.
Figure 1. Schematic workflow of mRNA display screening.
Repeat Steps 1 to 7 for several rounds.
Peptide Synthesis and Affinity Validation
Once candidate peptide sequences are identified, the process proceeds to peptide synthesis and affinity validation. Leveraging over 300 peptide modification capabilities (including phosphorylation, disulfide cyclization, fluorescent labeling, and various conjugations), MCE can rapidly complete custom synthesis of linear peptides, cyclic peptides, and complex modified peptides; standard HPLC-MS dual quality control and COA reports ensure the purity and sequence accuracy of every candidate peptide.
Following synthesis delivery, MCE provides multi-platform label-free molecular interaction analysis services, including Surface Plasmon Resonance (SPR), for real-time determination of key parameters such as affinity (KD), association rate (ka), and dissociation rate (kd). Through an integrated “sequence → synthesis → validation” delivery model, customers receive functional peptide molecules that are ready for downstream functional assays.
Figure 2. Schematic of peptide synthesis and affinity validation.
Service Scope and Advantages
| Service Content | Timeline | ||
|---|---|---|---|
| One-Stop Integrated Delivery | Library Screening |
1）Affinity incubation, washing, elution, amplification 2）3–5 rounds of screening 3）NGS sequencing and peptide sequence decoding |
7-8 weeks |
| Peptide Synthesis & Affinity Testing |
1）Synthesis of candidate peptides 2）Binding affinity measurement |
5-6 weeks | |
| Peptide Delivery | Delivery of complete project report and high‑affinity peptides | 1-2 weeks | |
Trillion-scale library (1014): Theoretical diversity of up to 1014, providing exceptionally high initial sequence coverage.
Conformationally constrained cyclization: Chemically bridged monocyclic rigid conformation that enhances target affinity.
Covalent coupling: mRNA and peptide covalently linked, reducing background noise and allowing weak binders to be captured and progressively enriched.
Cell-free system: Free from host cell toxicity constraints, compatible with toxic proteins and transmembrane targets.
One-stop delivery: Integrated from screening to synthesis and validation—no need to coordinate multiple vendors.
Online Consulting
mRNA Display Technology Service requires technical evaluation to confirm customized protocols and pricing. For detailed pricing or technical information, please email [email protected] or contact sales representatives directly.