Stepwise evolution of protein native structure with electrospray into the gas phase, 10
            <sup>−12</sup>
            to 10
            <sup>2</sup>
            s

Breuker, Kathrin; McLafferty, Fred W.

doi:10.1073/pnas.0807005105

Cited by 397 publications

(500 citation statements)

References 60 publications

(87 reference statements)

Supporting

Mentioning

465

Contrasting

Unclassified

Order By: Relevance

“…In low charge states, stabilization from ionic hydrogen bonds helps keep the protein ion folded. As the last few H ϩ ions are removed, this stabilization is lost, and the protein ion expands somewhat [10,11,47]. A similar explanation is as follows.…”

Section: Effect Of Charge Reduction Reaction On the Conformation Of Cmentioning

confidence: 57%

Effects of ion/ion proton transfer reactions on conformation of gas-phase cytochrome c ions

Zhao

Schieffer

Soyk

et al. 2010

J. Am. Soc. Mass Spectrom.

View full text Add to dashboard Cite

Positive ions from cytochrome c are studied in a 3-D ion trap/ion mobility (IM)/quadrupoletime-of-flight (TOF) instrument with three independent ion sources. The IM separation allows measurement of the cross section of the ions. Ion/ion reactions in the 3-D ion trap that remove protons cause the cytochrome c ions to refold gently without other degradation of protein structure, i.e., fragmentation or loss of heme group or metal ion. The conformation(s) of the product ions generated by ion/ion reactions in a given charge state are similar regardless of whether the cytochrome c ions are originally in ϩ8 or ϩ9 charge states. In the lower charge states (ϩ1 to ϩ5) cytochrome c ions made by the ion/ion reaction yield a single IM peak with cross section of ϳ1110 to 1180 Å 2 , even if the original ϩ8 ion started with multiple conformations. The conformation expands slightly when the charge state is reduced from ϩ5 to ϩ1. For product ions in the ϩ6 to ϩ8 charge states, ions created from higher charge states (ϩ9 to ϩ16) by ion/ion reaction produce more compact conformation(s) in somewhat higher abundances compared with those produced directly by the electrospray ionization ( [5][6][7][8][9], and native electron capture dissociation (NECD) [10,11]. Of these methods, IM provides a direct way to examine the gas-phase conformation of the ions by probing the average cross-section of the protein ions via collisions with buffer gas [3,4]. Early IM research on protein folding and unfolding was done with an IMquadrupole instrument [1]. To study ions in lower charge states than those made directly from the electrospray ionization (ESI) source, a basic collision gas (e.g., acetophenone or 7-methyl-1,3,5-triazabicyclo 4,4,0] dec-5-ene, MTBD) [12] was introduced into the source region. The neutral gas extracted protons from the protein ion and created lower charge state ions through proton transfer reactions in the source. In these studies, the reactions took place only in the atmospheric pressure ion source interface region. Thus, control and variation of the reaction time and extent of reaction were difficult, and only certain reagent species were available.Gas-phase ion/ion reactions provide another dimension for gas-phase bioanalysis by MS. To date, these reactions have been mainly used to simplify complex MS/MS spectra [13,14] or generate fragments for structural assignment [15,16] by methods like electrontransfer dissociation (ETD) [17][18][19].Recent instrumentation improvements have greatly extended the type of structural information and number of possible experiments available in this area. The development of a 3-D trap-IM-time of flight (TOF) instrument allows time-dependent studies of gas-phase protein ions, including folding, unfolding and structural transitions [20 -23]. A multi-stage IMS-MS instrument [24,25] provides two important new functions. First, a protein ion with a specific structure can be selected by IMS, then activated and separated in the next drift region. Second, "state-to-state" structural

show abstract

Section: Effect Of Charge Reduction Reaction On the Conformation Of Cmentioning

confidence: 57%

Effects of ion/ion proton transfer reactions on conformation of gas-phase cytochrome c ions

Zhao

Schieffer

Soyk

et al. 2010

J. Am. Soc. Mass Spectrom.

View full text Add to dashboard Cite

show abstract

“…The main advantages of this method are the high resolution together with the multiple ion activation modes available, such as (1) CID in the external collision cell or in the ICR cell through sustained off resonance irradiation (SORI) under CID conditions [23], (2) infrared multiphoton dissociation (IRMPD) [24], and (3) for positive ions, electron-capture dissociation (ECD) [25,26]. The latter has revealed particularly powerful for the structural characterization of peptides and proteins [27], given the ability to cleave the peptide backbone while leaving intact labile side-chain modifications, or without disrupting the noncovalent interactions involved in the three-dimensional structure of proteins [28,29]. In order to develop an analytical method to unambiguously characterize topoisomeric peptides by mass spectrometry, the fragmentation patterns MccJ25, capistruin, and their corresponding non-lasso topoisomers MccJ25-lcm and capistruin-lcm were analyzed by ESI-FT-ICR-MS upon CID, SORI CID, IRMPD, and ECD.…”

Section: G N W H G T a P D W F F N Y Y W G F I G W G N D I F G H Y S mentioning

confidence: 99%

Topoisomer Differentiation of Molecular Knots by FTICR MS: Lessons from Class II Lasso Peptides

Zirah

Afonso

Linne

et al. 2011

J. Am. Soc. Mass Spectrom.

View full text Add to dashboard Cite

Lasso peptides constitute a class of bioactive peptides sharing a knotted structure where the C-terminal tail of the peptide is threaded through and trapped within an N-terminal macrolactam ring. The structural characterization of lasso structures and differentiation from their unthreaded topoisomers is not trivial and generally requires the use of complementary biochemical and spectroscopic methods. Here we investigated two antimicrobial peptides belonging to the class II lasso peptide family and their corresponding unthreaded topoisomers: microcin J25 (MccJ25), which is known to yield two-peptide product ions specific of the lasso structure under collisioninduced dissociation (CID), and capistruin, for which CID does not permit to unambiguously assign the lasso structure. The two pairs of topoisomers were analyzed by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICR MS) upon CID, infrared multiple photon dissociation (IRMPD), and electron capture dissociation (ECD). CID and ECD spectra clearly permitted to differentiate MccJ25 from its non-lasso topoisomer MccJ25-Icm, while for capistruin, only ECD was informative and showed different extent of hydrogen migration (formation of c•/z from c/z • ) for the threaded and unthreaded topoisomers. The ECD spectra of the triply-chargedMccJ25 and MccJ25-lcm showed a series of radical b-type product ions ðb 0 I n Þ. We proposed that these ions are specific of cyclic-branched peptides and result from a dual c/z • and y/b dissociation, in the ring and in the tail, respectively. This work shows the potentiality of ECD for structural characterization of peptide topoisomers, as well as the effect of conformation on hydrogen migration subsequent to electron capture.

show abstract

“…"classic" electrospray mass spectrometry). 11,12 This charge separation process is variously labeled pneumatic or sonic spray ionization. 2,13,14 Such charged microdroplets subsequently evaporate solvent in the chamber while being drawn to the electrically polarized inlet of the mass spectrometer with increasing acceleration.…”

mentioning

confidence: 99%

Dry Deposition of Biogenic Terpenes via Cationic Oligomerization on Environmental Aqueous Surfaces

Enami

Hoffmann

Colussi

2012

J. Phys. Chem. Lett.

View full text Add to dashboard Cite

The products we observe are produced when the gaseous terpenes collide with the intact electroneutral aqueous jets as they emerge from the nozzle, i.e., before jets are broken up by the nebulizer gas. Since mass spectrometers detect net charge, the first step is the separation of pre-existing anions from cations in the electroneutral inflowing solutions. This is accomplished via the pneumatic breakup of the aqueous jet by a fast nebulizer gas that shears the outermost jet layers into droplets carrying net charges of either sign. These net charges are proportional to the concentrations of the protonated terpenes and their oligomers produced during gas-liquid collisions. Such droplets have a distribution of sizes and net charges 1,2 and, together, possess more surface and electrostatic energies than the original jet at the expense of the kinetic energy lost by the nebulizer gas. Since the nebulizer gas can fragment the jet but not

show abstract

Stepwise evolution of protein native structure with electrospray into the gas phase, 10 ⁻¹² to 10 ² s

Cited by 397 publications

References 60 publications

Effects of ion/ion proton transfer reactions on conformation of gas-phase cytochrome c ions

Effects of ion/ion proton transfer reactions on conformation of gas-phase cytochrome c ions

Topoisomer Differentiation of Molecular Knots by FTICR MS: Lessons from Class II Lasso Peptides

Dry Deposition of Biogenic Terpenes via Cationic Oligomerization on Environmental Aqueous Surfaces

Contact Info

Product

Resources

About

Stepwise evolution of protein native structure with electrospray into the gas phase, 10 −12 to 10 2 s

Cited by 397 publications

References 60 publications

Effects of ion/ion proton transfer reactions on conformation of gas-phase cytochrome c ions

Effects of ion/ion proton transfer reactions on conformation of gas-phase cytochrome c ions

Topoisomer Differentiation of Molecular Knots by FTICR MS: Lessons from Class II Lasso Peptides

Dry Deposition of Biogenic Terpenes via Cationic Oligomerization on Environmental Aqueous Surfaces

Contact Info

Product

Resources

About

Stepwise evolution of protein native structure with electrospray into the gas phase, 10 ⁻¹² to 10 ² s