Effects of transition metal cationization on peptide dissociation by mass spectrometry

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dc.contributorVincent, John B.
dc.contributorBusenlehner, Laura S.
dc.contributorSzulczewski, Gregory J.
dc.contributorO'Donnell, Janis M.
dc.contributor.advisorCassady, Carolyn J.
dc.contributor.authorWatson, Heather Malone
dc.contributor.otherUniversity of Alabama Tuscaloosa
dc.date.accessioned2017-03-01T16:23:53Z
dc.date.available2017-03-01T16:23:53Z
dc.date.issued2011
dc.descriptionElectronic Thesis or Dissertationen_US
dc.description.abstractPeptide sequencing is fundamental to understanding a protein's structure and function. The field of proteomics is dedicated to how these aspects relate to human health and disease. Unfortunately, the majority of peptides and proteins are not fully sequenced. In mass spectrometry, this is often due to spectral complications and incomplete fragmentation. There is a need to develop new sample preparation techniques or dissociation methods to increase sequence information. The dissociation of transition metal-cationized peptides by collision-induced dissociation (CID), electron-transfer dissociation (ETD), and electron-transfer collisionally activated dissociation (ETcaD) has been investigated in a quadrupole ion trap (QIT). The resulting mass spectra provide a wealth of information about the primary structures of the peptides. Using transition metal ions as cationizing reagents proves beneficial to peptide sequencing by CID and, in some cases, is better than the analysis of protonated species. For instance, spectra obtained from CID of singly and doubly charged Cu(II)-heptaalanine ions, [M + Cu - H]^+ and [M + Cu]^2, are complementary and together provide cleavage at every residue and no neutral losses. This contrasts with protonated heptaalanine, [M + H]^+, which results in fewer backbone cleavages by CID and does not allow sequencing of the first three residues. Multiply charged precursor ions are required in order to carry out ETD and ETcaD. This can be problematic for acidic or neutral peptides. This work demonstrates that addition of transition metals as a cationizing reagent allows peptides to be submitted to ETD and ETcaD that do not otherwise form multiply charged precursors. ETD spectra were less complex than those produced by CID. ETcaD increases backbone cleavages for all samples studied relative to ETD. In addition, complexes that result in very few cleavages by CID are cleaved at every residue when submitted to ETcaD. Evidence for macrocyclic metallated a- and b-ions is found in ETD and ETcaD spectra in the form of nonsequential product ions. The sequence (pEEEEGDD) of the peptide component of biologically derived low-molecular-weight chromium binding substance (LMWCr) is obtained as a result of extensive mass spectrometric studies. LMWCr is proposed to be involved in carbohydrate metabolism. The sequencing of the peptide component of LMWCr by MS represents a potentially significant milestone towards understanding the pharmacological role of chromium at a molecular level.en_US
dc.format.extent225 p.
dc.format.mediumelectronic
dc.format.mimetypeapplication/pdf
dc.identifier.otheru0015_0000001_0000768
dc.identifier.otherWatson_alatus_0004D_10887
dc.identifier.urihttps://ir.ua.edu/handle/123456789/1272
dc.languageEnglish
dc.language.isoen_US
dc.publisherUniversity of Alabama Libraries
dc.relation.hasversionborn digital
dc.relation.ispartofThe University of Alabama Electronic Theses and Dissertations
dc.relation.ispartofThe University of Alabama Libraries Digital Collections
dc.rightsAll rights reserved by the author unless otherwise indicated.en_US
dc.subjectAnalytical chemistry
dc.subjectChemistry
dc.subjectBiochemistry
dc.titleEffects of transition metal cationization on peptide dissociation by mass spectrometryen_US
dc.typethesis
dc.typetext
etdms.degree.departmentUniversity of Alabama. Department of Chemistry
etdms.degree.disciplineChemistry
etdms.degree.grantorThe University of Alabama
etdms.degree.leveldoctoral
etdms.degree.namePh.D.

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