Abstract
Phage display (PD) is frequently used to discover peptides capable of binding to biological protein targets. The structural characterization of peptide-protein complexes is often challenging due to their low binding affinities and high structural flexibility. Here, we investigate the use of hydrogen/deuterium exchange mass spectrometry (HDX-MS) to characterize interactions of low affinity peptides with their cognate protein targets. The HDX-MS workflow was optimized to accurately detect low-affinity peptide-protein interactions by use of ion mobility, electron transfer dissociation, non-binding control peptides and statistical analysis of replicate data. We show that HDX-MS can identify regions in the two epigenetic regulator proteins KDM4C and KDM1A that are perturbed through weak interactions with PD-identified peptides. Two peptides cause reduced HDX on opposite sides of the active site of KDM4C, indicating distinct binding modes. In contrast, the perturbation site of another PD-selected peptide inhibiting the function of KDM1A maps to a GST-tag. Our results demonstrate that HDX-MS can validate and map weak peptide-protein interactions, and pave the way for understanding and optimizing the binding of peptide scaffolds identified through PD and similar ligand discovery approaches.
Original language | English |
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Journal | Analytical Chemistry |
Volume | 86 |
Issue number | 23 |
Pages (from-to) | 11734-11741 |
Number of pages | 8 |
ISSN | 0003-2700 |
DOIs | |
Publication status | Published - 2 Dec 2014 |