Integrated tools for higher order structure determination by cross-link analysis - Summary
The use of mass spectrometry (MS) for quantitative protein characterization has increased
dramatically; identifying and quantifying thousands of proteins is no longer a heroic task nor is
characterizing therapeutic proteins in detail. Due to widely available software, quantitative mass
spectrometry has become routine and widely used for addressing questions in basic biology,
translational medicine and drug development. MS Methods are now poised to have similar
impact on the study of protein-protein interaction and higher order structure (HOS)
determination.
In particular, crosslinking mass spectrometry, which obtains distance and accessibility
constraints from two-ended chemical modifications, is emerging as a powerful tool to map
protein-protein interaction interfaces. Recent years have seen large improvements in crosslink
mass spectrometry. Yet despite these advances, crosslink analysis is not yet a technique that
has found widespread use, due to a range of problems such as the low abundance of
crosslinked peptides, unavailability of proprietary reagents, the need for different search
algorithms adopted to specific cross-linkers, and the difficulty of reliably characterizing
crosslinked peptide spectra.
To alleviate these problems and democratize the use of crosslinking, we propose to develop
standardized and effective methods for crosslinking in conjunction with sensitive and accurate
search algorithms, incorporated into our well-established Byonic search engine. Our algorithms
will support almost all commercially available crosslinking chemistries and most major peptide
fragmentation methods (ETD, CAD/HCD, EthcD), as well as cleavable and non-cleavable
crosslinkers. The near universal applicability and ease-of-use of the software will promote rapid
adoption of crosslinking mass spectrometry in academic research and biopharmaceutical
development.