Backbone NMR assignment of the yeast expressed Fab fragment of the NISTmAb reference antibody

Biomol NMR Assign. 2023 Jun;17(1):75-81. doi: 10.1007/s12104-023-10123-9. Epub 2023 Mar 1.


The monoclonal antibody (mAb) protein class has become a primary therapeutic platform for the production of new life saving drug products. MAbs are comprised of two domains: the antigen-binding fragment (Fab) and crystallizable fragment (Fc). Despite the success in the clinic, NMR assignments of the complete Fab domain have been elusive, in part due to problems in production of properly folded, triply-labeled 2H,13C,15N Fab domain. Here, we report the successful recombinant expression of a triply-labeled Fab domain, derived from the standard IgG1κ known as NISTmAb, in yeast. Using the 2H,13C,15N Fab domain, we assigned 94% of the 1H, 13C, and 15N backbone atoms.

Keywords: Backbone assignments; Biologics; Fab domain; NISTmAb.

MeSH terms

  • Antibodies, Monoclonal / chemistry
  • Immunoglobulin Fab Fragments* / chemistry
  • Magnetic Resonance Spectroscopy
  • Nuclear Magnetic Resonance, Biomolecular
  • Saccharomyces cerevisiae*


  • Immunoglobulin Fab Fragments
  • Antibodies, Monoclonal