Characterization of purified c-type heme-containing peptides and identification of c-type heme-attachment sites in Shewanella oneidenis cytochromes using mass spectrometry
We describe methods for mass spectrometric identification of heme-containing peptides from digests of c-type cytochromes that contain the CXXCH(X = any amino acid) sequence motif. Analysis of purified standard heme-containing peptides showed that the charged heme group was present both before and after peptide fragmentation in the gas phase. The heme fragment ion yielded the most abundant MS/MS peak for standard heme-containing peptides with one amino acid difference (DAA=1) for both 2+ and 3+ peptide charge states and the extent of heme loss during peptide fragmentation was affected by both sequence and charge. A modified search strategy was evaluated with tryptic digests of one known and two unknown cytochromes from Shewanella oneidenis, demonstrating that this approach can be generally applied for identification of c-type heme-containing peptides from complex samples.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 15020617
- Report Number(s):
- PNNL-SA-43808; KP1102010; TRN: US200521%%198
- Journal Information:
- Journal of Proteome Research, Vol. 4, Issue 3
- Country of Publication:
- United States
- Language:
- English
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