{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/71434"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/71434","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Structure and Function of Macromolecular Antifreezes (Peptide, Glycopeptide, Fish)","abstract":"Many polar fishes are protected from freezing by peptide or glycopeptide antifreezes which inhibit ice growth. The relationship between the structures of these molecules and the mechanism by which they work in investigated in this thesis.","abstract_html":"Many polar fishes are protected from freezing by peptide or glycopeptide antifreezes which inhibit ice growth. The relationship between the structures of these molecules and the mechanism by which they work in investigated in this thesis.","abstract_has_math":false,"creators":["Schrag, Joseph D."],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Physiology","degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2014,"date_issued":"2014-12-16T06:45:47Z","date_published":"2014-12-16T06:45:47Z","updated_at":"2026-07-22T22:26:04Z","subjects":["Chemistry, Biochemistry"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["(UMI)AAI8502291"],"render_values":[{"text":"(UMI)AAI8502291","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/71434","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Schrag, Joseph D."]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2014-12-16T06:45:47Z","10000-01-01","1984"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Physiology"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Chemistry, Biochemistry"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/71434","(UMI)AAI8502291"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Many polar fishes are protected from freezing by peptide or glycopeptide antifreezes which inhibit ice growth. The relationship between the structures of these molecules and the mechanism by which they work in investigated in this thesis.","Glycopeptide antifreezes range in molecular weight from 2600-33,000 daltons and most are polymers of the tripeptide ala-ala-thr. Each threonine is glycosidically linked to the disaccharide galactose-N-acetylgalactosamine. The glycopeptide antifreezes from Microgadus tomcod and Eleginus gracilis are unique, however, in that they contain arginine. Determination of the amino acid sequences of these antifreezes indicates that glycopeptide antifreeze structure is highly conserved. Arginine occasionally replaces the glycosidically linked threonine in these sequences, but the basic tripeptide repeat is otherwise maintained.","The large glycopeptides are more efficient inhibitors of ice growth than are the small proline containing glycopeptides. Although the secondary structures of the glycopeptides are uncertain, some investigators have proposed some ordered structures and have suggested that the proline residues of the small glycopeptides may disrupt this structure and reduce their effectiveness. The results presented in this study, however, indicate that the observed differences in effectiveness between different sizes of glycopeptide antifreezes can be attributed entirely to differences in molecular size rather than differences in conformation.","A model of peptide antifreeze function is based on the structure of the winter flounder peptide. Polar amino acids are periodically spaced in this peptide and the spacing of the polar residues in a helical conformation is presumed to allow efficient hydrogen bonding of the antifreeze of the ice surface. Some investigators predicted that all peptide antifreezes would be similarly arranged. Peptide antifreezes were isolated from the zoarcids Rhigophila dearborni and Lycodes polaris. No periodic placement of polar groups is evident in the amino acid sequences and CD indicates little or no helical structure in these peptides. The secondary structure of these peptides remains uncertain, but a large amount of (beta)-structure is predicted from the amino acid sequences. Peptide antifreeze structures clearly show substantial variation.","Made available in DSpace on 2014-12-16T06:45:47Z (GMT). No. of bitstreams: 1 8502291.pdf: 2951129 bytes, checksum: 27814cc40be01ca54bd9cd1d5027b1bb (MD5) Previous issue date: 1984","Embargo set by: Seth Robbins for item 71600 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","U of I Only","100 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1984."]},{"key":"dc:title","label":"Title","values":["Structure and Function of Macromolecular Antifreezes (Peptide, Glycopeptide, Fish)"]}]}],"canonical_facts":{"dc:creator":["Schrag, Joseph D."],"dc:date":["2014-12-16T06:45:47Z","10000-01-01","1984"],"dc:description":["Many polar fishes are protected from freezing by peptide or glycopeptide antifreezes which inhibit ice growth. The relationship between the structures of these molecules and the mechanism by which they work in investigated in this thesis.","Glycopeptide antifreezes range in molecular weight from 2600-33,000 daltons and most are polymers of the tripeptide ala-ala-thr. Each threonine is glycosidically linked to the disaccharide galactose-N-acetylgalactosamine. The glycopeptide antifreezes from Microgadus tomcod and Eleginus gracilis are unique, however, in that they contain arginine. Determination of the amino acid sequences of these antifreezes indicates that glycopeptide antifreeze structure is highly conserved. Arginine occasionally replaces the glycosidically linked threonine in these sequences, but the basic tripeptide repeat is otherwise maintained.","The large glycopeptides are more efficient inhibitors of ice growth than are the small proline containing glycopeptides. Although the secondary structures of the glycopeptides are uncertain, some investigators have proposed some ordered structures and have suggested that the proline residues of the small glycopeptides may disrupt this structure and reduce their effectiveness. The results presented in this study, however, indicate that the observed differences in effectiveness between different sizes of glycopeptide antifreezes can be attributed entirely to differences in molecular size rather than differences in conformation.","A model of peptide antifreeze function is based on the structure of the winter flounder peptide. Polar amino acids are periodically spaced in this peptide and the spacing of the polar residues in a helical conformation is presumed to allow efficient hydrogen bonding of the antifreeze of the ice surface. Some investigators predicted that all peptide antifreezes would be similarly arranged. Peptide antifreezes were isolated from the zoarcids Rhigophila dearborni and Lycodes polaris. No periodic placement of polar groups is evident in the amino acid sequences and CD indicates little or no helical structure in these peptides. The secondary structure of these peptides remains uncertain, but a large amount of (beta)-structure is predicted from the amino acid sequences. Peptide antifreeze structures clearly show substantial variation.","Made available in DSpace on 2014-12-16T06:45:47Z (GMT). No. of bitstreams: 1 8502291.pdf: 2951129 bytes, checksum: 27814cc40be01ca54bd9cd1d5027b1bb (MD5) Previous issue date: 1984","Embargo set by: Seth Robbins for item 71600 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","U of I Only","100 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1984."],"dc:identifier":["http://hdl.handle.net/2142/71434","(UMI)AAI8502291"],"dc:subject":["Chemistry, Biochemistry"],"dc:title":["Structure and Function of Macromolecular Antifreezes (Peptide, Glycopeptide, Fish)"],"dc:type":["text"],"thesis:degree_discipline":["Physiology"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:26:04Z"}