To assist with the complex task of characterizing protein-based biotherapuetics such as mAbs, the National Institute of Standards and Technology (NIST) in the USA undertook a holistic study using a humanized mAb, the NISTmAb, in 2016.
The study utilized the biophysical techniques most commonly employed during biotherapeutic development, and the NISTmAb is now available to biopharmaceutical companies as a representative reference molecule.
Applied Photophysics Ltd. had been approached by the NIST to contribute CD data to this project. A primary standard of the NISTmAb, PS 8670, was compared with the NISTmAb reference material, RM 8671.
As typical for mAbs, the far-UV spectrum is characteristic of a protein with high β-sheet content. However, the far-UV spectra contain information beyond secondary structure elements—signals of lower amplitude around and above 230 nm arise from disulfide bonds.