Format

Send to

Choose Destination
See comment in PubMed Commons below
Anal Chem. 2011 Jul 15;83(14):5617-23. doi: 10.1021/ac200719n. Epub 2011 Jun 21.

Ultrasensitive identification of localization variants of modified peptides using ion mobility spectrometry.

Author information

1
Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States.

Abstract

Localization of the modification sites on peptides is challenging, particularly when multiple modifications or mixtures of localization isomers (variants) are involved. Such variants commonly coelute in liquid chromatography and may be undistinguishable in tandem mass spectrometry (MS/MS) for lack of unique fragments. Here, we have resolved the variants of singly and doubly phosphorylated peptides employing drift tube ion mobility spectrometry (IMS) coupled to time-of-flight mass spectrometry. Even with a moderate IMS resolving power of ∼80-100, substantial separation was achieved for both 2+ and 3+ ions normally generated by electrospray ionization, including for the variants indistinguishable by MS/MS. Variants often exhibit a distribution of 3-D conformers, which can be adjusted for optimum IMS separation by prior field heating of ions in a funnel trap. The peak assignments were confirmed using MS/MS after IMS separation, but known species could be identified using just the ion mobility "tag". Avoiding the MS/MS step lowers the detection limit of localization variants to <100 amol, an order of magnitude better than that provided by electron transfer dissociation in an Orbitrap MS.

PMID:
21692493
PMCID:
PMC3136632
DOI:
10.1021/ac200719n
[Indexed for MEDLINE]
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for American Chemical Society Icon for PubMed Central
    Loading ...
    Support Center