title: Action-FRET: probing the molecular conformation of mass-selected gas-phase peptides with Förster resonance energy transfer detected by acceptor-specific fragmentation.
abstract: The use of Förster resonance energy transfer (FRET) as a probe of the structure of biological molecules through fluorescence measurements in solution is well-attested. The transposition of this technique to the gas phase is appealing since it opens the perspective of combining the structural accuracy of FRET with the specificity and selectivity of mass spectrometry (MS). Here, we report FRET results on gas-phase polyalanine ions obtained by measuring FRET efficiency through specific photofragmentation rather than fluorescence. The structural sensitivity of the method was tested using commercially available chromophores (QSY 7 and carboxyrhodamine 575) grafted on a series of small, alanine-based peptides of differing sizes. The photofragmentation of these systems was investigated through action spectroscopy, and their conformations were probed using ion mobility spectrometry (IMS) and Monte Carlo minimization (MCM) simulations. We show that specific excitation of the donor chromophore results in the observation of fragments that are specific to the electronic excitation of the acceptor chromophore. This shows that energy transfer took place between the two chromophores and hence that the action-FRET technique can be used as a new and sensitive probe of the structure of gas-phase biomolecules, which opens perspectives as a new tool in structural biology.
authors: Université de Lyon , F-69622 Lyon, France.
authors: Steven
authors: S
authors: Daly
authors: Frédéric
authors: F
authors: Poussigue
authors: Anne-Laure
authors: AL
authors: Simon
authors: Luke
authors: L
authors: MacAleese
authors: Franck
authors: F
authors: Bertorelle
authors: Fabien
authors: F
authors: Chirot
authors: Rodolphe
authors: R
authors: Antoine
authors: Philippe
authors: P
authors: Dugourd
mesh_terms: D031541:Fluorescence Resonance Energy Transfer; D005740:Gases / Q000737:chemistry*; D009010:Monte Carlo Method; D010455:Peptides / Q000032:analysis* / Q000737:chemistry; D012235:Rhodamines / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D005740:Gases; D010455:Peptides; D012235:Rhodamines; C019529:polyalanine