Versatile Labeling of Protein N-Termini for Site-specific Bioconjugation

Tech ID: 27604 / UC Case 2017-035-0

Invention Novelty

Improved subtiligase variants allow broad and versatile site-specific chemical modification or conjugation of proteins on their N-termini.

Value Proposition

Site-specific chemical modification of proteins is an enabling technology for drug design, chemical biology, cell biology, and materials science. The existing subtiligase technology selectively labels proteins on their N-termini with synthetic peptides. However, many of the N-terminal dipeptide sequences were inaccessible to subtiligase labeling due to incompatible sequences. Investigators at UCSF have made a significant improvement over current technology by engineering new subtiligase variants that allow bioconjugation to many more different N-terminal sequences and accept various peptide ester substrates. Notably, these include sequences that have an acidic residue at the N terminus, which is often the case for mammalian antibodies and therefore allows application in the production of antibody-drug conjugates.


  • Reactions proceed rapidly (minute time scale) under mild conditions that preserve protein function
  • Generates stable peptide bonds
  • Eliminates need for genetic engineering to introduce ligation tags
  • Compatible with different types of chemical modifications
  • Targets many additional N-terminal dipeptide sequences

Technology Description

The Wells Lab at UCSF has engineered new variants of subtiligase with altered N-terminal protein substrate specificity to enable broadened site-specific protein bioconjugation. These variants also have an increased or improved aminolysis to hydrolysis ratio (A/H ratio) compared to a wild-type subtiligase or a wild-type stabiligase. The use of these novel enzymes allows selective protein labeling on many more N-terminal sequences than were previously accessible to subtiligase labeling. The inventors have also developed an algorithm that facilitates the selection of appropriate subtiligase mutants for the N-terminal sequences of interest. Such site-specific bioconjugation can be used to link polypeptides to fluorophores, affinity handles, DNA barcodes, drug payloads, and reactive groups.

Looking for Partners

To develop & commercialize the subtiligase variants and their substrates as a kit or tool for site-specific protein conjugation to use in antibody-drug conjugation, drug design, and as a research tool for imaging, fluorescence assays, proteomic profiling and affinity pulldowns.

Stage of Development

Proof of concept

Data Availability

Under CDA / NDA

Patent Status

Country Type Number Dated Case
Patent Cooperation Treaty Published Application WO2018045200 03/08/2018 2017-035

Additional Patent Pending

Related Materials


Learn About UC TechAlerts - Save Searches and receive new technology matches


  • Weeks, Amy M.
  • Wells, James (Jim) A.

Other Information


Site-Specific Protein Labeling, Subtiligase, N-termini, Antibody-Drug Conjugation (ADC), Protein Profiling, Research Tools, Proteomics

Categorized As