Protein identification by 3D OrbiSIMS to facilitate in situ imaging and depth profiling

Nat Commun. 2020 Nov 17;11(1):5832. doi: 10.1038/s41467-020-19445-x. | PubMed

Anna M Kotowska¹, Gustavo F Trindade¹, Paula M Mendes², Philip M Williams¹, Jonathan W Aylott¹, Alexander G Shard³, Morgan R Alexander¹, David J Scurr⁴

1. School of Pharmacy, University of Nottingham, Nottingham, NG7 2RD, UK.
2. School of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
3. National Physical Laboratory, Hampton Road, Teddington, Middlesex, TW11 0LW, UK.
4. School of Pharmacy, University of Nottingham, Nottingham, NG7 2RD, UK. david.scurr@nottingham.ac.uk.

Abstract

Label-free protein characterization at surfaces is commonly achieved using digestion and/or matrix application prior to mass spectrometry. We report the assignment of undigested proteins at surfaces in situ using secondary ion mass spectrometry (SIMS). Ballistic fragmentation of proteins induced by a gas cluster ion beam (GCIB) leads to peptide cleavage producing fragments for subsequent OrbitrapTM analysis. In this work we annotate 16 example proteins (up to 272 kDa) by de novo peptide sequencing and illustrate the advantages of this approach by characterizing a protein monolayer biochip and the depth distribution of proteins in human skin.

Presented By Anna Kotowska | ORCID iD