Effects of transition metal cationization on peptide dissociation by mass spectrometry

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dc.contributor Vincent, John B.
dc.contributor Busenlehner, Laura S.
dc.contributor Szulczewski, Gregory J.
dc.contributor O'Donnell, Janis M.
dc.contributor.advisor Cassady, Carolyn J.
dc.contributor.author Watson, Heather Malone
dc.date.accessioned 2017-03-01T16:23:53Z
dc.date.available 2017-03-01T16:23:53Z
dc.date.issued 2011
dc.identifier.other u0015_0000001_0000768
dc.identifier.other Watson_alatus_0004D_10887
dc.identifier.uri https://ir.ua.edu/handle/123456789/1272
dc.description Electronic Thesis or Dissertation
dc.description.abstract Peptide 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.
dc.format.extent 225 p.
dc.format.medium electronic
dc.format.mimetype application/pdf
dc.language English
dc.language.iso en_US
dc.publisher University of Alabama Libraries
dc.relation.ispartof The University of Alabama Electronic Theses and Dissertations
dc.relation.ispartof The University of Alabama Libraries Digital Collections
dc.relation.hasversion born digital
dc.rights All rights reserved by the author unless otherwise indicated.
dc.subject.other Analytical chemistry
dc.subject.other Chemistry
dc.subject.other Biochemistry
dc.title Effects of transition metal cationization on peptide dissociation by mass spectrometry
dc.type thesis
dc.type text
etdms.degree.department University of Alabama. Department of Chemistry
etdms.degree.discipline Chemistry
etdms.degree.grantor The University of Alabama
etdms.degree.level doctoral
etdms.degree.name Ph.D.


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