Using intrinsic X-ray absorption spectral differences to identify and map peptides and proteins

Jacob Stewart-Ornstein, Adam P. Hitchcock, Daniel Hernández Cruz, Peter Henklein, Joerg Overhage, Kai Hilpert, John D. Hale, Robert Hancock

Research output: Contribution to journalArticle

64 Citations (Scopus)

Abstract

The intrinsic variation in the near-edge X-ray absorption fine structure (NEXAFS) spectra of peptides and proteins provide an opportunity to identify and map them in various biological environments, without additional labeling. In principle, with sufficiently accurate spectra, peptides (<50 amino acids) or proteins with unusual sequences (e.g., cysteine- or methionine-rich) should be differentiable from other proteins, since the NEXAFS spectrum of each amino acid is distinct. To evaluate the potential for this approach, we have developed X-SpecSim, a tool for quantitatively predicting the C, N, and O 1s NEXAFS spectra of peptides and proteins from their sequences. Here we present the methodology for predicting such spectra, along with tests of its precision using comparisons to the spectra of various proteins and peptides. The C 1s, N 1s, and O 1s spectra of two novel antimicrobial peptides, Indolicidin (ILPWKWPWWPWRR-NH2) and Sub6 (RWWKIWVIR-WWR-NH2), as well as human serum albumin and fibrinogen are reported and interpreted. The ability to identify, differentiate, and quantitatively map an antimicrobial peptide against a background of protein is demonstrated by a scanning transmission X-ray microscopy study of a mixture of albumin and sub6.

Original languageEnglish
Pages (from-to)7691-7699
Number of pages9
JournalJournal of Physical Chemistry B
Volume111
Issue number26
DOIs
Publication statusPublished - 5 Jul 2007
Externally publishedYes

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry

Cite this

Stewart-Ornstein, J., Hitchcock, A. P., Cruz, D. H., Henklein, P., Overhage, J., Hilpert, K., ... Hancock, R. (2007). Using intrinsic X-ray absorption spectral differences to identify and map peptides and proteins. Journal of Physical Chemistry B, 111(26), 7691-7699. https://doi.org/10.1021/jp0720993