Services

Engineered Scaffold Protein Library Construction

Inquiry

Where an antibody-like scaffold is not required, a small natural protein or protein domain can serve as the framework for a designed library. Randomizing a defined set of positions within a stable, well-folded scaffold produces a constrained library: every member shares the same backbone fold, but the randomized surface presents a wide range of shapes and chemistries. Compared with an unconstrained random library, a scaffold-restricted library tends to stay folded and soluble while still exploring many sequences, which improves the chance of finding a binder or a ligand with a new function against a target molecule.

We build scaffold libraries on naturally occurring small proteins and domains that are known to tolerate surface variation, and we express them in the display system that fits the project. The framework choice, the positions randomized, and the display format are decided together with the target and the intended use of the selected molecule.

Suitable Scaffold Sources

Bacterial receptor domains – compact, robust domains that tolerate loop and surface randomization.
DNA-binding proteins – structured domains whose surface can be diversified to recognize new partners.
Protease inhibitors – small, stable inhibitors whose binding loops can be reshaped for novel specificity.
Other small stable domains – selected with the project's folding and expression needs in mind.

Display and Selection Systems

System	What it provides	Fit
Phage display	Genotype and phenotype linked on a filamentous phage	Mature, well-characterized selection against immobilized or captured targets
Ribosome display	No transformation step; library stays as mRNA–ribosome–protein complexes	Very large libraries and in vitro selection without cloning
mRNA display	Covalent mRNA–protein linkage for each variant	In vitro selection with a defined genotype–phenotype covalent bond
Cell-surface display	Variant presented on a microbial or mammalian cell surface	Selection by fluorescence-based sorting of whole cells
Mammalian / yeast two-hybrid	Interaction read out inside a cell	Intracellular or protein–protein interaction screening

Construction Approach

Choose the framework – select a scaffold whose fold and expression suit the target.
Define randomization – pick the positions to diversify and the amino acid mixture at each.
Build the library – assemble the diversified gene pool using a triplet-based mutagenesis scheme that controls the spectrum of variants.
Verify the library – confirm capacity and the correctness of the randomized region before selection.
Select and recover – pan or sort against the target and recover the enriched sequences.

Why a Scaffold Library

Folded, soluble variants – the shared framework keeps members structured during selection.
New functions – compared with an unconstrained library, scaffold restriction favors ligands with a defined fold and sometimes a new activity toward the target.
Higher-affinity routes – a stable framework gives a clean starting point for later affinity maturation.
Format flexibility – the same scaffold can be moved between display systems as the project requires.

Applications

Targeted binder discovery – non-immunoglobulin binders for targets that are hard to address with antibodies.
Reagent and diagnostic development – stable, well-expressed binding domains.
Therapeutic lead generation – a structured starting scaffold for optimization.
Basic research tools – engineered domains that recognize a defined molecular feature.

The service is for research only, not for clinical use.