Showing 41 - 50 of 59 Items
Development of a Schiff base Synthetic Platform for 8-phenyliminonaphthol Photoacids Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2023-01-01
Creator: Ibrahim G. Saleh
Access: Access restricted to the Bowdoin Community
Arginine methylation of yeast mRNA-binding protein Npl3 directly affects its function, nuclear export, and intranuclear protein interactions
Date: 2005-09-02
Creator: Anne E. McBride, Jeffrey T. Cook, Elizabeth A. Stemmler, Kate L. Rutledge, Kelly A., McGrath, Jeffrey A. Rubens
Access: Open access
- Arginine methylation can affect both nucleocytoplasmic transport and protein-protein interactions of RNA-binding proteins. These effects are seen in cells that lack the yeast hnRNP methyltransferase (HMT1), raising the question of whether effects on specific proteins are direct or indirect. The presence of multiple arginines in individual methylated proteins also raises the question of whether overall methylation or methylation of a subset of arginines affects protein function. We have used the yeast mRNA-binding protein Npl3 to address these questions in vivo. Matrix-assisted laser desorption/ionization Fourier transform mass spectrometry was used to identify 17 methylated arginines in Npl3 purified from yeast: whereas 10 Arg-Gly-Gly (RGG) tripeptides were exclusively dimethylated, variable levels off methylation were found for 5 RGG and 2 RG motif arginines. We constructed a set of Npl3 proteins in which subsets of the RGG arginines were mutated to lysine. Expression of these mutant proteins as the sole form of Npl3 specifically affected growth of a strain that requires Hmtl. Although decreased growth generally correlated with increased numbers of Arg-to-Lys mutations, lysine substitutions in the N terminus of the RGG domain showed more severe effects. Npl3 with all 15 RGG arginines mutated to lysine exited the nucleus independent of Hmtl, indicating a direct effect of methylation on Npl3 transport. These mutations also resulted in a decreased, methylation-independent interaction of Npl3 with transcription elongation factor Tho2 and inhibited Npl3 self-association. These results support a model in which arginine methylation facilitates Npl3 export directly by weakening contacts with nuclear proteins. © 2005 by The American Society for Biochemistry and Molecular Biology, Inc.
Predicting Anionic Pharmaceutical Sorption to Soils Using Probe Compounds Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2022-01-01
Creator: Francesca Ann Cawley
Access: Access restricted to the Bowdoin Community
The Photocatalytic Degradation of Ibuprofen and Three Beta-Blockers using BiOCl: An Investigation into the Mechanisms Responsible for Photocatalytic Activity Access to this record is restricted to members of the Bowdoin community. Log in here to view.
- Restriction End Date: 2027-06-01
Date: 2022-01-01
Creator: Jeffrey Charles Price
Access: Access restricted to the Bowdoin Community
Characterization and Quantification of AST-C Peptides in Homarus americanus Using Mass Spectrometry
Date: 2015-05-01
Creator: Amanda Howard
Access: Open access
- Neuropeptides are small signaling molecules found throughout the nervous system that influence animal behavior. Using the American lobster, Homarus americanus, as a model system, this research focused on an allatostatin type-C (AST-C) peptide, pQIRYHQCYFNPISCF (disulfide bond between underlined cysteine residues), and a structurally similar crustacean peptide, SYWKQCAFNAVSCFamide. These neuropeptides influence cardiac muscle contraction patterns and stomatogastric nervous system activity in the lobster. To understand their roles, this study sought to develop a method to quantify peptides in the pericardial organ (PO) and other crustacean tissues. Overall analysis involved microdissection to isolate tissues, tissue extraction, extract purification and concentration, and analysis by chip-based nano-electrospray ionization-liquid chromatography-mass spectrometry (nanoESI-LC-MS). In the present study, pQIRYHQCYFNPISCF was identified in the PO. To quantify target peptides, internal standards were tested as recovery and calibration references. However, experiments with pQIRYHQCYFNPISCF and other peptides showed evidence of adsorptive losses during sample preparation and analysis, with improvements in recovery resulting from the use of isopropanol-prewashed polypropylene vials. Preliminary results also suggested that introducing polyethylene glycol (PEG) in solution reduced adsorptive losses for hydrophobic peptides, but may have compromised hydrophilic peptide detection. Future directions include characterizing other sources of analyte loss and developing techniques to recover these signals. Since both target peptides as detected in the lobster are post-translationally modified, other directions include identifying modified and unmodified forms of these peptides in H. americanus. Ultimately, quantifying AST-C peptides and viii identifying their modified and unmodified forms will help explain how neuropeptides regulate behavior within the lobster and more complex systems.
Identifying crustacean neuropeptides and precursor-related peptides by LC/MS: An investigation of strategies for extraction and orthogonal separations Access to this record is restricted to members of the Bowdoin community. Log in here to view.
- Restriction End Date: 2028-06-01
Date: 2023-01-01
Creator: Emily Grace Herndon
Access: Access restricted to the Bowdoin Community
Discovery and characterization of novel crustin family antimicrobial peptides (AMPs) in the American lobster, Homarus americanus, using transcriptomics and peptidomics Access to this record is restricted to members of the Bowdoin community. Log in here to view.
- Restriction End Date: 2027-06-01
Date: 2022-01-01
Creator: Emily Yuan-ann Pan
Access: Access restricted to the Bowdoin Community
Photoacidic properties of 8-amino-2-naphthol in imidazolium salts Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2023-01-01
Creator: Rachel E Nealon
Access: Access restricted to the Bowdoin Community
The Determination of the Aqueous Oxidation Potentials of Aniline and Sixteen of its Derivatives via Ultrafast Cyclic Voltammetry to Model the Photocatalyzed Degradation of Organic Pollutants in Natural Bodies of Water Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2014-05-01
Creator: Joshua V Pondick
Access: Access restricted to the Bowdoin Community
Probing mucin-type O-linked glycosylation in living animals
Date: 2006-03-28
Creator: Danielle H. Dube, Jennifer A. Prescher, Chi M. Quang, Carolyn R. Bertozzi
Access: Open access
- Changes in O-linked protein glycosylation are known to correlate with disease states but are difficult to monitor in a physiological setting because of a lack of experimental tools. Here, we report a technique for rapid profiling of O-linked glycoproteins in living animals by metabolic labeling with N-azidoacetylgalactosamine (GalNAz) followed by Staudinger ligation with phosphine probes. After injection of mice with a peracetylated form of GalNAz, azide-labeled glycoproteins were observed in a variety of tissues, including liver, kidney, and heart, in serum, and on isolated splenocytes. B cell glycoproteins were robustly labeled with GalNAz but T cell glycoproteins were not, suggesting fundamental differences in glycosylation machinery or metabolism. Furthermore, GalNAz-labeled B cells could be selectively targeted with a phosphine probe by Staudinger ligation within the living animal. Metabolic labeling with GalNAz followed by Staudinger ligation provides a means for proteomic analysis of this posttranslational modification and for identifying O-linked glycoprotein fingerprints associated with disease. © 2006 by The National Academy of Sciences of the USA.