2011
Combined Electron Transfer Dissociation–Collision-Induced Dissociation Fragmentation in the Mass Spectrometric Distinction of Leucine, Isoleucine, and Hydroxyproline Residues in Peptide Natural Products
Gupta K, Kumar M, Chandrashekara K, Krishnan KS, Balaram P. Combined Electron Transfer Dissociation–Collision-Induced Dissociation Fragmentation in the Mass Spectrometric Distinction of Leucine, Isoleucine, and Hydroxyproline Residues in Peptide Natural Products. Journal Of Proteome Research 2011, 11: 515-522. PMID: 22111579, DOI: 10.1021/pr200091v.Peer-Reviewed Original ResearchConceptsIsobaric residuesMass spectrometric peptide sequencingNatural peptide librariesPeptide natural productsCrude peptide mixturesTandem mass spectrometric methodMass spectrometric distinctionMass spectrometric methodRadical ionsIsobaric leucineElectron transferCollisional activationDissociation fragmentationPeptide mixturesNatural productsNominal massSpectrometric methodLiquid chromatographyPeptide sequencingPresence of hydroxyprolineIonsPeptide libraryDifferent peptidesDissociation approachHydroxyproline residues
2010
Disulfide Bond Assignments by Mass Spectrometry of Native Natural Peptides: Cysteine Pairing in Disulfide Bonded Conotoxins
Gupta K, Kumar M, Balaram P. Disulfide Bond Assignments by Mass Spectrometry of Native Natural Peptides: Cysteine Pairing in Disulfide Bonded Conotoxins. Analytical Chemistry 2010, 82: 8313-8319. PMID: 20843009, DOI: 10.1021/ac101867e.Peer-Reviewed Original ResearchConceptsS bond cleavageBond cleavageNatural peptidesDisulfide bondsProduct ion yieldsMass spectral fragmentationDisulfide bond assignmentsDisulfide pairingFragment ionsStructure elucidationPeptide backboneBond assignmentDissociation conditionsMass spectrometryMultiple disulfide bondsCysteine pairingsSpectral fragmentationPossible disulfideMultiple cysteine residuesNative peptideAnalytical methodologyBondsCorrect disulfide pairingIon yieldFurther fragmentation