Computational design of a pH-sensitive IgG binding protein

TitleComputational design of a pH-sensitive IgG binding protein
Publication TypeJournal Article
Year of Publication2013
AuthorsStrauch, E. - M., Fleishman S. J., & Baker D.
JournalProceedings of the National Academy of Sciences of the United States of America
Date Published2013 Dec 31
KeywordsPrimary Publication

Computational design provides the opportunity to program protein-protein interactions for desired applications. We used de novo protein interface design to generate a pH-dependent Fc domain binding protein that buries immunoglobulin G (IgG) His-433. Using next-generation sequencing of naïve and selected pools of a library of design variants, we generated a molecular footprint of the designed binding surface, confirming the binding mode and guiding further optimization of the balance between affinity and pH sensitivity. In biolayer interferometry experiments, the optimized design binds IgG with a Kd of ∼4 nM at pH 8.2, and approximately 500-fold more weakly at pH 5.5. The protein is extremely stable, heat-resistant and highly expressed in bacteria, and allows pH-based control of binding for IgG affinity purification and diagnostic devices.


Alternate JournalProc. Natl. Acad. Sci. U.S.A.
Strauch-1313605111_PNAS_13W.pdf1.32 MB