{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/28690"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/28690","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Thermal and denaturation studies of the time-resolved fluorescence decay of superoxide dismutase","abstract":"Time-resolved fluorescence of single tryptophan proteins have demonstrated the complexity of protein dynamic and structure. In particular, for some single tryptophan proteins, their fluorescence decay is best described by a distribution of fluorescence lifetimes rather than one or two lifetimes. Furthermore, the behavior of the lifetime distributions with environmental changes is consistent with the hypothesis that proteins fluctuate between a hierarchy of many conformational substates. With this scenario as a theoretical framework, the correlations between protein dynamic and structure are investigated by studying the time-resolved fluorescence and anisotropy decay of the single tryptophan (Trp) residue of human superoxide dismutase (HSOD) over a wide range of temperatures and at different denaturant concentrations. First, it is demonstrated that the center of the lifetime distribution can characterize the average deactivation environment of the excited Trp-protein system. A qualitative model is introduced to explain the time-resolved fluorescence decay of HSOD in 80% glycerol over a wide range of temperatures. The dynamical model features isoenergetic conformational substates separated by a hierarchy of energy barriers. The HSOD system is also investigated as a function of denaturant concentration in aqueous solution. As a function of guanidine hydrochloride (GdHCl), the width of the fluorescence lifetime distribution of HSOD displays a maximum which is not coincident with the fully denatured form of HSOD at 6.5M GdHCl. Furthermore, the width for the fully denatured form of HSOD is greater than that of the native form. This is consistent with the scenario that more conformational substates are being created upon denaturation of HSOD. HSOD is a dimeric protein and it was observed that the width of the lifetime distribution of HSOD at intermediate GdHCl concentrations increased with decreasing protein concentration. In addition, the secondary structure of HSOD at intermediate GdHCl concentration does not change with protein concentration. These results suggest that HSOD display structural microheterogeneity which is consistent with the hypothesis of conformational substates. Further analysis show that, during denaturation, the monomeric form of HSOD is an intermediate which displays native-like secondary structure and :fluctuating tertiary structure; i.e., the monomeric form of HSOD is a molten globule.","abstract_html":"Time-resolved fluorescence of single tryptophan proteins have demonstrated the complexity of protein dynamic and structure. In particular, for some single tryptophan proteins, their fluorescence decay is best described by a distribution of fluorescence lifetimes rather than one or two lifetimes. Furthermore, the behavior of the lifetime distributions with environmental changes is consistent with the hypothesis that proteins fluctuate between a hierarchy of many conformational substates. With this scenario as a theoretical framework, the correlations between protein dynamic and structure are investigated by studying the time-resolved fluorescence and anisotropy decay of the single tryptophan (Trp) residue of human superoxide dismutase (HSOD) over a wide range of temperatures and at different denaturant concentrations. First, it is demonstrated that the center of the lifetime distribution can characterize the average deactivation environment of the excited Trp-protein system. A qualitative model is introduced to explain the time-resolved fluorescence decay of HSOD in 80% glycerol over a wide range of temperatures. The dynamical model features isoenergetic conformational substates separated by a hierarchy of energy barriers. The HSOD system is also investigated as a function of denaturant concentration in aqueous solution. As a function of guanidine hydrochloride (GdHCl), the width of the fluorescence lifetime distribution of HSOD displays a maximum which is not coincident with the fully denatured form of HSOD at 6.5M GdHCl. Furthermore, the width for the fully denatured form of HSOD is greater than that of the native form. This is consistent with the scenario that more conformational substates are being created upon denaturation of HSOD. HSOD is a dimeric protein and it was observed that the width of the lifetime distribution of HSOD at intermediate GdHCl concentrations increased with decreasing protein concentration. In addition, the secondary structure of HSOD at intermediate GdHCl concentration does not change with protein concentration. These results suggest that HSOD display structural microheterogeneity which is consistent with the hypothesis of conformational substates. Further analysis show that, during denaturation, the monomeric form of HSOD is an intermediate which displays native-like secondary structure and :fluctuating tertiary structure; i.e., the monomeric form of HSOD is a molten globule.","abstract_has_math":false,"creators":["Silva, Norberto De Jesus"],"institution":null,"degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Physics","degree_department":null,"school":null,"contributors":["Gratton, E."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2012,"date_issued":"2012-01-25T19:56:47Z","date_published":"2012-01-25T19:56:47Z","updated_at":"2026-07-22T22:25:27Z","subjects":["human superoxide dismutase","fluorescence decay"],"languages":["en"],"rights":["1993 Norberto De Jesus Silva"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/28690","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Gratton, E."]},{"key":"dc:creator","label":"Author","values":["Silva, Norberto De Jesus"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2012-01-25T19:56:47Z","10000-01-01","1993"]},{"key":"dc:type","label":"Dc Type","values":["Dissertation / Thesis","text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Physics"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["human superoxide dismutase","fluorescence decay"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["1993 Norberto De Jesus Silva"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/28690"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Time-resolved fluorescence of single tryptophan proteins have demonstrated the complexity of protein dynamic and structure. In particular, for some single tryptophan proteins, their fluorescence decay is best described by a distribution of fluorescence lifetimes rather than one or two lifetimes. Furthermore, the behavior of the lifetime distributions with environmental changes is consistent with the hypothesis that proteins fluctuate between a hierarchy of many conformational substates. With this scenario as a theoretical framework, the correlations between protein dynamic and structure are investigated by studying the time-resolved fluorescence and anisotropy decay of the single tryptophan (Trp) residue of human superoxide dismutase (HSOD) over a wide range of temperatures and at different denaturant concentrations. First, it is demonstrated that the center of the lifetime distribution can characterize the average deactivation environment of the excited Trp-protein system. A qualitative model is introduced to explain the time-resolved fluorescence decay of HSOD in 80% glycerol over a wide range of temperatures. The dynamical model features isoenergetic conformational substates separated by a hierarchy of energy barriers. The HSOD system is also investigated as a function of denaturant concentration in aqueous solution. As a function of guanidine hydrochloride (GdHCl), the width of the fluorescence lifetime distribution of HSOD displays a maximum which is not coincident with the fully denatured form of HSOD at 6.5M GdHCl. Furthermore, the width for the fully denatured form of HSOD is greater than that of the native form. This is consistent with the scenario that more conformational substates are being created upon denaturation of HSOD. HSOD is a dimeric protein and it was observed that the width of the lifetime distribution of HSOD at intermediate GdHCl concentrations increased with decreasing protein concentration. In addition, the secondary structure of HSOD at intermediate GdHCl concentration does not change with protein concentration. These results suggest that HSOD display structural microheterogeneity which is consistent with the hypothesis of conformational substates. Further analysis show that, during denaturation, the monomeric form of HSOD is an intermediate which displays native-like secondary structure and :fluctuating tertiary structure; i.e., the monomeric form of HSOD is a molten globule.","Submitted by Carolyn Rauber (crauber2@illinois.edu) on 2012-01-25T19:56:47Z No. of bitstreams: 1 1993_silva.pdf: 4737310 bytes, checksum: 225255157e3c79951e97468239687ded (MD5)","Made available in DSpace on 2012-01-25T19:56:47Z (GMT). No. of bitstreams: 1 1993_silva.pdf: 4737310 bytes, checksum: 225255157e3c79951e97468239687ded (MD5) Previous issue date: 1993","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Rauber (crauber2@illinois.edu) on 2012-01-25T19:56:47Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:09:59-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: dissertation","dissertation","U of I Only"]},{"key":"dc:title","label":"Title","values":["Thermal and denaturation studies of the time-resolved fluorescence decay of superoxide dismutase"]}]}],"canonical_facts":{"dc:contributor":["Gratton, E."],"dc:creator":["Silva, Norberto De Jesus"],"dc:date":["2012-01-25T19:56:47Z","10000-01-01","1993"],"dc:description":["Time-resolved fluorescence of single tryptophan proteins have demonstrated the complexity of protein dynamic and structure. In particular, for some single tryptophan proteins, their fluorescence decay is best described by a distribution of fluorescence lifetimes rather than one or two lifetimes. Furthermore, the behavior of the lifetime distributions with environmental changes is consistent with the hypothesis that proteins fluctuate between a hierarchy of many conformational substates. With this scenario as a theoretical framework, the correlations between protein dynamic and structure are investigated by studying the time-resolved fluorescence and anisotropy decay of the single tryptophan (Trp) residue of human superoxide dismutase (HSOD) over a wide range of temperatures and at different denaturant concentrations. First, it is demonstrated that the center of the lifetime distribution can characterize the average deactivation environment of the excited Trp-protein system. A qualitative model is introduced to explain the time-resolved fluorescence decay of HSOD in 80% glycerol over a wide range of temperatures. The dynamical model features isoenergetic conformational substates separated by a hierarchy of energy barriers. The HSOD system is also investigated as a function of denaturant concentration in aqueous solution. As a function of guanidine hydrochloride (GdHCl), the width of the fluorescence lifetime distribution of HSOD displays a maximum which is not coincident with the fully denatured form of HSOD at 6.5M GdHCl. Furthermore, the width for the fully denatured form of HSOD is greater than that of the native form. This is consistent with the scenario that more conformational substates are being created upon denaturation of HSOD. HSOD is a dimeric protein and it was observed that the width of the lifetime distribution of HSOD at intermediate GdHCl concentrations increased with decreasing protein concentration. In addition, the secondary structure of HSOD at intermediate GdHCl concentration does not change with protein concentration. These results suggest that HSOD display structural microheterogeneity which is consistent with the hypothesis of conformational substates. Further analysis show that, during denaturation, the monomeric form of HSOD is an intermediate which displays native-like secondary structure and :fluctuating tertiary structure; i.e., the monomeric form of HSOD is a molten globule.","Submitted by Carolyn Rauber (crauber2@illinois.edu) on 2012-01-25T19:56:47Z No. of bitstreams: 1 1993_silva.pdf: 4737310 bytes, checksum: 225255157e3c79951e97468239687ded (MD5)","Made available in DSpace on 2012-01-25T19:56:47Z (GMT). No. of bitstreams: 1 1993_silva.pdf: 4737310 bytes, checksum: 225255157e3c79951e97468239687ded (MD5) Previous issue date: 1993","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Rauber (crauber2@illinois.edu) on 2012-01-25T19:56:47Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:09:59-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: dissertation","dissertation","U of I Only"],"dc:identifier":["http://hdl.handle.net/2142/28690"],"dc:language":["en"],"dc:rights":["1993 Norberto De Jesus Silva"],"dc:subject":["human superoxide dismutase","fluorescence decay"],"dc:title":["Thermal and denaturation studies of the time-resolved fluorescence decay of superoxide dismutase"],"dc:type":["Dissertation / Thesis","text"],"thesis:degree_discipline":["Physics"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."]},"updated_at":"2026-07-22T22:25:27Z"}