{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/18922"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/18922","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Conformational relaxation in heme proteins : ligand rebinding above the glass transition","abstract":"Below the glass-transition temperature of the solvent, heme proteins are frozen into static conformations, and ligand rebinding is well described with a time- and temperature-independent distribution of enthalpic barriers, g(H). This work addresses the relaxation of the enthalpic barriers that sets in near the glass transition of the solvent as significant protein motions occur on the time scale of rebinding. As the heme domes fully toward its equilibrium deoxy structure, the distribution of enthalpies changes with time and temperature. A simple phenomenological model is used to describe MbCO rebinding at all temperatures above 50 K. Like the glassy relaxations observed in MbCO upon a sudden pressure release, the relaxation of all barriers to higher enthalpy is nonexponential in time and does not obey an Arrhenius relation. The extent of the enthalpic shift is consistent with a prediction based upon the inhomogeneous rebinding of band III, the charge transfer band observed in unligated Mb near 13100 cm-1 • Geminate rebinding from 160 to 290 K is well described in MbCO by a relaxation of all barriers by 9.3 kJ /mol without invoking any wells along the reaction coordinate representing ligand migration into the protein matrix. A simple argument is used to estimate the rate coefficient for ligand escape into the solvent. It, too, is found to have a non-Arrhenius temperature dependence. A numerical inversion technique is used to obtain the distribution of dissociated lifetimes, f(logr), from kinetics at a single temperature. The Maximum Entropy Method is outlined, tested with synthetic data, and applied to MbCO kinetics at various temperatures. The f distribution obtained at 90 K indicates that the tail of the g( H) distribution measured in the Soret is a manifestation of rebinding to A3, the slowest of the three predominant bound conformations to rebind. Several features are resolved in the f(logr) distributions obtained above the glass transition of the solvent.","abstract_html":"Below the glass-transition temperature of the solvent, heme proteins are frozen into static conformations, and ligand rebinding is well described with a time- and temperature-independent distribution of enthalpic barriers, g(H). This work addresses the relaxation of the enthalpic barriers that sets in near the glass transition of the solvent as significant protein motions occur on the time scale of rebinding. As the heme domes fully toward its equilibrium deoxy structure, the distribution of enthalpies changes with time and temperature. A simple phenomenological model is used to describe MbCO rebinding at all temperatures above 50 K. Like the glassy relaxations observed in MbCO upon a sudden pressure release, the relaxation of all barriers to higher enthalpy is nonexponential in time and does not obey an Arrhenius relation. The extent of the enthalpic shift is consistent with a prediction based upon the inhomogeneous rebinding of band III, the charge transfer band observed in unligated Mb near 13100 cm-1 • Geminate rebinding from 160 to 290 K is well described in MbCO by a relaxation of all barriers by 9.3 kJ /mol without invoking any wells along the reaction coordinate representing ligand migration into the protein matrix. A simple argument is used to estimate the rate coefficient for ligand escape into the solvent. It, too, is found to have a non-Arrhenius temperature dependence. A numerical inversion technique is used to obtain the distribution of dissociated lifetimes, f(logr), from kinetics at a single temperature. The Maximum Entropy Method is outlined, tested with synthetic data, and applied to MbCO kinetics at various temperatures. The f distribution obtained at 90 K indicates that the tail of the g( H) distribution measured in the Soret is a manifestation of rebinding to A3, the slowest of the three predominant bound conformations to rebind. Several features are resolved in the f(logr) distributions obtained above the glass transition of the solvent.","abstract_has_math":false,"creators":["Steinbach, Peter John"],"institution":null,"degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Physics","degree_department":null,"school":null,"contributors":["Frauenfelder, Hans"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-05-05T14:39:24Z","date_published":"2011-05-05T14:39:24Z","updated_at":"2026-07-22T22:25:11Z","subjects":["conformational relaxation","heme proteins","ligand binding","glass transition"],"languages":["en"],"rights":["1990 Peter John Steinbach"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["3476379"],"render_values":[{"text":"3476379","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/18922","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Frauenfelder, Hans"]},{"key":"dc:creator","label":"Author","values":["Steinbach, Peter John"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011-05-05T14:39:24Z","10000-01-01","1990"]},{"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":["conformational relaxation","heme proteins","ligand binding","glass transition"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["1990 Peter John Steinbach"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["3476379","http://hdl.handle.net/2142/18922"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Below the glass-transition temperature of the solvent, heme proteins are frozen into static conformations, and ligand rebinding is well described with a time- and temperature-independent distribution of enthalpic barriers, g(H). This work addresses the relaxation of the enthalpic barriers that sets in near the glass transition of the solvent as significant protein motions occur on the time scale of rebinding. As the heme domes fully toward its equilibrium deoxy structure, the distribution of enthalpies changes with time and temperature. A simple phenomenological model is used to describe MbCO rebinding at all temperatures above 50 K. Like the glassy relaxations observed in MbCO upon a sudden pressure release, the relaxation of all barriers to higher enthalpy is nonexponential in time and does not obey an Arrhenius relation. The extent of the enthalpic shift is consistent with a prediction based upon the inhomogeneous rebinding of band III, the charge transfer band observed in unligated Mb near 13100 cm-1 • Geminate rebinding from 160 to 290 K is well described in MbCO by a relaxation of all barriers by 9.3 kJ /mol without invoking any wells along the reaction coordinate representing ligand migration into the protein matrix. A simple argument is used to estimate the rate coefficient for ligand escape into the solvent. It, too, is found to have a non-Arrhenius temperature dependence. A numerical inversion technique is used to obtain the distribution of dissociated lifetimes, f(logr), from kinetics at a single temperature. The Maximum Entropy Method is outlined, tested with synthetic data, and applied to MbCO kinetics at various temperatures. The f distribution obtained at 90 K indicates that the tail of the g( H) distribution measured in the Soret is a manifestation of rebinding to A3, the slowest of the three predominant bound conformations to rebind. Several features are resolved in the f(logr) distributions obtained above the glass transition of the solvent.","Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-05-05T14:39:24Z No. of bitstreams: 1 1990_Steinbach.pdf: 1256645 bytes, checksum: 6d6af3d07394d7ce4bbe8414c692d06e (MD5)","Made available in DSpace on 2011-05-05T14:39:24Z (GMT). No. of bitstreams: 1 1990_Steinbach.pdf: 1256645 bytes, checksum: 6d6af3d07394d7ce4bbe8414c692d06e (MD5) Previous issue date: 1990","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Mead (cmead2@illinois.edu) on 2011-05-05T14:39:24Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:12:18-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: Thesis","Thesis","U of I Only"]},{"key":"dc:title","label":"Title","values":["Conformational relaxation in heme proteins : ligand rebinding above the glass transition"]}]}],"canonical_facts":{"dc:contributor":["Frauenfelder, Hans"],"dc:creator":["Steinbach, Peter John"],"dc:date":["2011-05-05T14:39:24Z","10000-01-01","1990"],"dc:description":["Below the glass-transition temperature of the solvent, heme proteins are frozen into static conformations, and ligand rebinding is well described with a time- and temperature-independent distribution of enthalpic barriers, g(H). This work addresses the relaxation of the enthalpic barriers that sets in near the glass transition of the solvent as significant protein motions occur on the time scale of rebinding. As the heme domes fully toward its equilibrium deoxy structure, the distribution of enthalpies changes with time and temperature. A simple phenomenological model is used to describe MbCO rebinding at all temperatures above 50 K. Like the glassy relaxations observed in MbCO upon a sudden pressure release, the relaxation of all barriers to higher enthalpy is nonexponential in time and does not obey an Arrhenius relation. The extent of the enthalpic shift is consistent with a prediction based upon the inhomogeneous rebinding of band III, the charge transfer band observed in unligated Mb near 13100 cm-1 • Geminate rebinding from 160 to 290 K is well described in MbCO by a relaxation of all barriers by 9.3 kJ /mol without invoking any wells along the reaction coordinate representing ligand migration into the protein matrix. A simple argument is used to estimate the rate coefficient for ligand escape into the solvent. It, too, is found to have a non-Arrhenius temperature dependence. A numerical inversion technique is used to obtain the distribution of dissociated lifetimes, f(logr), from kinetics at a single temperature. The Maximum Entropy Method is outlined, tested with synthetic data, and applied to MbCO kinetics at various temperatures. The f distribution obtained at 90 K indicates that the tail of the g( H) distribution measured in the Soret is a manifestation of rebinding to A3, the slowest of the three predominant bound conformations to rebind. Several features are resolved in the f(logr) distributions obtained above the glass transition of the solvent.","Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-05-05T14:39:24Z No. of bitstreams: 1 1990_Steinbach.pdf: 1256645 bytes, checksum: 6d6af3d07394d7ce4bbe8414c692d06e (MD5)","Made available in DSpace on 2011-05-05T14:39:24Z (GMT). No. of bitstreams: 1 1990_Steinbach.pdf: 1256645 bytes, checksum: 6d6af3d07394d7ce4bbe8414c692d06e (MD5) Previous issue date: 1990","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Mead (cmead2@illinois.edu) on 2011-05-05T14:39:24Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:12:18-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: Thesis","Thesis","U of I Only"],"dc:identifier":["3476379","http://hdl.handle.net/2142/18922"],"dc:language":["en"],"dc:rights":["1990 Peter John Steinbach"],"dc:subject":["conformational relaxation","heme proteins","ligand binding","glass transition"],"dc:title":["Conformational relaxation in heme proteins : ligand rebinding above the glass transition"],"dc:type":["Dissertation / Thesis","text"],"thesis:degree_discipline":["Physics"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."]},"updated_at":"2026-07-22T22:25:11Z"}