Supported Protein Formats

We support single-chain binder formats and Fabs, expressed in cell-free E. coli or yeast.

We test a wide range of binder formats, from antibody-derived fragments such as VHHs and Fabs to engineered scaffolds, de novo designed proteins, and peptides. All designs are produced in a cell-free expression system, E. coli or yeast, which is excellent for single-chain formats and Fabs. Constructs of roughly 8 to 700 amino acids are supported.

We do not produce full bivalent IgGs. The Fc region does not express well in cell-free, so an intact IgG is not a format we can run. If you have IgG sequences, submit them as scFvs and/or Fabs instead: take the VH and VL domains and send those as the constructs you want expressed.

Format support

Format	Supported	Notes
VHH / nanobody	Yes	Single-chain and well suited to cell-free expression. The most common format we run.
scFv	Yes	Single-chain. Submit the full construct including your linker of choice.
Fab	Yes	Heavy and light chains are supplied as a paired construct. Carries a per-design surcharge.
Minibinder / de novo protein	Yes	Engineered scaffolds and computationally designed binders.
Peptide	Yes	Run routinely. The shortest design we have measured binding on is 8 amino acids.
Full bivalent IgG	No	The Fc does not express in cell-free. Submit the VH and VL domains as an scFv or a Fab instead.

Submitting sequences

We do not clone your designs into fixed scaffolds. You submit the full amino acid sequence you want expressed, exactly as you want it made. For a VHH, that means the complete VHH sequence rather than only the CDRs. For a Fab, supply the heavy and light chains as a paired construct so they are expressed together.

Every design also receives a standard tag before expression. See Construct and tag design for what gets appended and where it sits.

Keep each construct within the supported range of approximately 8 to 700 amino acids. Sequences outside this range should be discussed with us before you submit your experiment.

Expression system

Designs are expressed cell-free, which is what makes short turnaround times and large design panels possible. Two systems are available:

System	Notes
Cell-free E. coli	The default, and the right choice for most single-chain formats and Fabs.
Cell-free yeast	Available as an alternative when a design expresses poorly in E. coli.

If you are not sure which system suits your designs, ask us and we will advise before you submit.

Mammalian cell line expression (CHO) is in development and not yet available. Contact us for the current status if your program depends on it.

Cost and format

Format does not change the per-sequence rate. The rate is set by the number of designs you submit, not by which format you choose or how long your sequences are. The one exception is Fab, which carries a per-design surcharge on top of the standard rate.

For current rates and the Fab surcharge, see the Adaptyv Bio services page.

Cell-free expression

How the expression system works and what it means for your constructs.

Target proteins

What we can test your binders against, and how to source a custom target.

FAQ

Can I submit full-length IgG sequences?

Not as intact IgGs. The Fc does not express well in our cell-free system, so we cannot produce full bivalent IgGs. The route is to express your IgG sequences as scFvs and/or Fabs instead. Take the VH and VL domains from your IgG and submit them either as an scFv, with the two joined by a linker of your choice, or as a paired Fab construct.

Do you offer mammalian or CHO expression?

Not yet. Mammalian cell line expression (CHO) is in development. Today all expression runs cell-free, in either E. coli or yeast. Contact us for the current status if mammalian expression is a requirement for your program.

Does format change the price?

The rate is set by the number of designs you submit, not by format or sequence length. Fab is the exception and carries a per-design surcharge. See the services page for current pricing.

Do you clone my design into a scaffold?

No. You submit the full sequence you want expressed and we express exactly that, plus the standard tag described in Construct and tag design.