2012
Distinct Disulfide Isomers of μ‑Conotoxins KIIIA and KIIIB Block Voltage-Gated Sodium Channels
Khoo KK, Gupta K, Green BR, Zhang MM, Watkins M, Olivera BM, Balaram P, Yoshikami D, Bulaj G, Norton RS. Distinct Disulfide Isomers of μ‑Conotoxins KIIIA and KIIIB Block Voltage-Gated Sodium Channels. Biochemistry 2012, 51: 9826-9835. PMID: 23167564, PMCID: PMC4131687, DOI: 10.1021/bi301256s.Peer-Reviewed Original ResearchConceptsΜ-Conotoxin KIIIADisulfide connectivityCollision-induced dissociation fragmentationDisulfide isomersNuclear magnetic resonance dataNative disulfide connectivityDisulfide patternVenom-derived peptidesDisulfide bond connectivitySame disulfide connectivityOxidative foldingDissociation fragmentationMagnetic resonance dataBond connectivityMultiple disulfide bondsMinor productsMajor isomerSolution structureActive peptidesIsomersΜ-conotoxinsResonance dataKIIIAVenom of ConusDisulfide bonds
2011
Mass spectrometric identification of an intramolecular disulfide bond in thermally inactivated triosephosphate isomerase from a thermophilic organism Methanocaldococcus jannaschii
Banerjee M, Gupta K, Balaram H, Balaram P. Mass spectrometric identification of an intramolecular disulfide bond in thermally inactivated triosephosphate isomerase from a thermophilic organism Methanocaldococcus jannaschii. Rapid Communications In Mass Spectrometry 2011, 25: 1915-1923. PMID: 21698673, DOI: 10.1002/rcm.5058.Peer-Reviewed Original ResearchConceptsMethanocaldococcus jannaschiiTriosephosphate isomeraseDisulfide bond formationIntramolecular disulfide bondsCysteine thiol groupsMonomer molecular massThree-dimensional structureThermophilic enzymesMass spectrometric identificationMS/MS analysisTetrameric enzymeTertiary structureMolecular massDisulfide bridgesDisulfide-bonded moleculesDisulfide bondsMonomeric massJannaschiiCircular dichroismComplete lossSpectrometric identificationIsomeraseEnzymeTryptic digestDa difference
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