LTQ XL ETD鉴定C-MYC和CTD肽段中的O-GlcNAc和磷酸化位点

简介：

Purpose: Demonstrate the utility of Electron Transfer Dissociation (ETD) for mapping of neighboring phosphorylated and O-glycosylation sites in peptides.

Methods: Synthetic peptides bearing different posttranslational modifications (PTMs) were analyzed by direct infusion and nESI using a Thermo Scientific LTQ XL mass spectrometer equipped with an ETD option (Thermo Scientific).

Results: Dissociation induced by ETD yields extensive peptide sequence information and in addition preserves labile PTMs. The exact sites of O-linked glycosylation and phosphorylation were unambiguously identified in this work.

仪器：

Thermo Scientific LTQ XL linear ion trap mass spectrometer with ETD and nESI source

结论：

Electron transfer dissociation demonstrated excellent capabilities for mapping neighboring phosphorylated and O-GlcNacylated sites in peptides without chemical derivatization, regardless of charge state.

The exact site of O-glycosylation in the CTD–OGlcNAc peptide was determined to be Serine 5 using ETD on the 2+ species with supplemental activation.

High confidence results for ETD data were obtained from the database search by using both BioWorks 3.3.1 (SEQUEST) and Mascot.

Successful ETD fragmentation and sequencing of larger peptides (~25 amino acids) can be performed by selecting optimal charge state species.