Use of different proteases working in acidic conditions to improve sequence coverage and resolution in hydrogen/deuterium exchange of large proteins
Article first published online: 7 OCT 2003
Copyright © 2003 John Wiley & Sons, Ltd.
Rapid Communications in Mass Spectrometry
Volume 17, Issue 21, pages 2387–2393, 15 November 2003
How to Cite
Cravello, L., Lascoux, D. and Forest, E. (2003), Use of different proteases working in acidic conditions to improve sequence coverage and resolution in hydrogen/deuterium exchange of large proteins. Rapid Commun. Mass Spectrom., 17: 2387–2393. doi: 10.1002/rcm.1207
- Issue published online: 7 OCT 2003
- Article first published online: 7 OCT 2003
- Manuscript Accepted: 30 AUG 2003
- Manuscript Revised: 27 AUG 2003
- Manuscript Received: 5 AUG 2003
The combination of hydrogen exchange and mass spectrometry has been widely used in structural biology, providing views on protein structure and protein dynamics. One of the constraints is to use proteases working at low pH and low temperature to limit back-exchange during proteolysis. Although pepsin works in these conditions and is currently used in such experiments, sequence coverage is not always complete especially for large proteins, and the spatial resolution of the exchange rate is limited by the size of the resulting peptides. In this study we tried two other proteases, protease type XIII from Aspergillus saitoi and protease type XVIII from Rhizhopus species. The penicillin-binding protein X (PBP-2X*), a 77-kDa protein, was selected as a model. Like pepsin, neither of these proteases is really specific, but we found very good reproducibility in the digestion pattern. Compared with using pepsin alone, combining the results of the three independent proteolyses increased the coverage for the peptide mapping, thus avoiding missing some potentially interesting regions of the protein. Furthermore, we obtained a better spatial resolution for deuterium incorporation data, specifying accurately the deuterated regions. Copyright © 2003 John Wiley & Sons, Ltd.