{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/22068"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/22068","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"The F(430) cofactor of methyl coenzyme M reductase: Ligand binding to the nickel and chemical modification of the tetrapyrrole substituents","abstract":"Chemical and spectroscopic studies on the nickel enzyme methyl-CoM reductase from M. thermoautotrophicum (strain $\\Delta$H) were undertaken to better characterize the nickel site. The major goals of this work are two-fold: (1) To further characterize the molecular and electronic structure of the methyl-CoM reductase nickel cofactor F$\\sb{430}$ as isolated and in the holoenzyme; (2) To probe the possible roles of the F$\\sb{430}$ cofactor in the methyl-CoM reductase-catalyzed reduction of CH$\\sb3$SCoM to CH$\\sb4$. In addition, the electronic and magnetic properties of the nickel, and the iron-sulfur centers in the different redox states of methyl viologen-reducing hydrogenase from the same bacterium were investigated.","abstract_html":"Chemical and spectroscopic studies on the nickel enzyme methyl-CoM reductase from M. thermoautotrophicum (strain $\\Delta$H) were undertaken to better characterize the nickel site. The major goals of this work are two-fold: (1) To further characterize the molecular and electronic structure of the methyl-CoM reductase nickel cofactor F$\\sb{430}$ as isolated and in the holoenzyme; (2) To probe the possible roles of the F$\\sb{430}$ cofactor in the methyl-CoM reductase-catalyzed reduction of CH$\\sb3$SCoM to CH$\\sb4$. In addition, the electronic and magnetic properties of the nickel, and the iron-sulfur centers in the different redox states of methyl viologen-reducing hydrogenase from the same bacterium were investigated.","abstract_has_math":true,"creators":["Hamilton, Cristi Lynn"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Chemistry","degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-05-07T13:27:56Z","date_published":"2011-05-07T13:27:56Z","updated_at":"2026-07-22T22:25:19Z","subjects":["Chemistry, Analytical","Chemistry, Inorganic","Biophysics, General"],"languages":["eng"],"rights":["Copyright 1990 Hamilton, Cristi Lynn"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["AAI9021693","(UMI)AAI9021693"],"render_values":[{"text":"AAI9021693","href":null,"code":true},{"text":"(UMI)AAI9021693","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/22068","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Hamilton, Cristi Lynn"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011-05-07T13:27:56Z","10000-01-01","1990"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Chemistry"]},{"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, Analytical","Chemistry, Inorganic","Biophysics, General"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 1990 Hamilton, Cristi Lynn"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["AAI9021693","(UMI)AAI9021693","http://hdl.handle.net/2142/22068"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Chemical and spectroscopic studies on the nickel enzyme methyl-CoM reductase from M. thermoautotrophicum (strain $\\Delta$H) were undertaken to better characterize the nickel site. The major goals of this work are two-fold: (1) To further characterize the molecular and electronic structure of the methyl-CoM reductase nickel cofactor F$\\sb{430}$ as isolated and in the holoenzyme; (2) To probe the possible roles of the F$\\sb{430}$ cofactor in the methyl-CoM reductase-catalyzed reduction of CH$\\sb3$SCoM to CH$\\sb4$. In addition, the electronic and magnetic properties of the nickel, and the iron-sulfur centers in the different redox states of methyl viologen-reducing hydrogenase from the same bacterium were investigated.","The electronic and magnetic properties of methyl-CoM reductase, F$\\sb{430}$ and various ligated forms at F$\\sb{430}$ were measured using variable-temperature magnetic circular dichroism (MCD) spectroscopy. Low-temperature magnetization data allowed the determination of the axial zero-field splitting parameter, D, of the S = 1 ground state of enzyme-bound F$\\sb{430}$ as well as bis-ligand complexes of the isolated cofactor. The values of D suggest oxygenic axial ligation to F$\\sb{430}$ in the holoenzyme.","To evaluate the role of F$\\sb{430}$ in substrate binding, the affinity of native F$\\sb{430}$, diepimeric F$\\sb{430}$, and F$\\sb{560}$ for different types of axial ligands and the conformational changes associated with axial ligation were investigated using uv/visible and circular dichroism spectroscopy. Differences in ligand binding affinities among the F$\\sb{430}$ isomers can be explained by macrocyclic conformational differences.","To solubilize F$\\sb{430}$ in nonaqueous solvents, the five peripheral carboxylates have been amidated with a number of alkylamines using a carbodiimide coupling method. These amides should be useful in evaluating the possible role of F$\\sb{430}$ as electron transfer agent and preliminary investigations are discussed.","MCD and EPR studies on oxidized and H$\\sb2$- and dithionite-reduced forms of the methyl viologen-reducing hydrogenase are presented. These studies provide the first direct spectroscopic evidence of the presence of S $>$ ${1\\over2}$ (4Fe-4S) $\\sp{1+}$ clusters in the reduced enzyme as well as suggest a spin interaction between these clusters and the nickel site.","Made available in DSpace on 2011-05-07T13:27:56Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9021693.pdf: 11155291 bytes, checksum: c539988db74d70d1e2d0ea08aebc47e0 (MD5) Previous issue date: 1990","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:55:06Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:25:39-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission","ETDs are only available to UIUC Users without author permission","U of I Only"]},{"key":"dc:title","label":"Title","values":["The F(430) cofactor of methyl coenzyme M reductase: Ligand binding to the nickel and chemical modification of the tetrapyrrole substituents"]}]}],"canonical_facts":{"dc:creator":["Hamilton, Cristi Lynn"],"dc:date":["2011-05-07T13:27:56Z","10000-01-01","1990"],"dc:description":["Chemical and spectroscopic studies on the nickel enzyme methyl-CoM reductase from M. thermoautotrophicum (strain $\\Delta$H) were undertaken to better characterize the nickel site. The major goals of this work are two-fold: (1) To further characterize the molecular and electronic structure of the methyl-CoM reductase nickel cofactor F$\\sb{430}$ as isolated and in the holoenzyme; (2) To probe the possible roles of the F$\\sb{430}$ cofactor in the methyl-CoM reductase-catalyzed reduction of CH$\\sb3$SCoM to CH$\\sb4$. In addition, the electronic and magnetic properties of the nickel, and the iron-sulfur centers in the different redox states of methyl viologen-reducing hydrogenase from the same bacterium were investigated.","The electronic and magnetic properties of methyl-CoM reductase, F$\\sb{430}$ and various ligated forms at F$\\sb{430}$ were measured using variable-temperature magnetic circular dichroism (MCD) spectroscopy. Low-temperature magnetization data allowed the determination of the axial zero-field splitting parameter, D, of the S = 1 ground state of enzyme-bound F$\\sb{430}$ as well as bis-ligand complexes of the isolated cofactor. The values of D suggest oxygenic axial ligation to F$\\sb{430}$ in the holoenzyme.","To evaluate the role of F$\\sb{430}$ in substrate binding, the affinity of native F$\\sb{430}$, diepimeric F$\\sb{430}$, and F$\\sb{560}$ for different types of axial ligands and the conformational changes associated with axial ligation were investigated using uv/visible and circular dichroism spectroscopy. Differences in ligand binding affinities among the F$\\sb{430}$ isomers can be explained by macrocyclic conformational differences.","To solubilize F$\\sb{430}$ in nonaqueous solvents, the five peripheral carboxylates have been amidated with a number of alkylamines using a carbodiimide coupling method. These amides should be useful in evaluating the possible role of F$\\sb{430}$ as electron transfer agent and preliminary investigations are discussed.","MCD and EPR studies on oxidized and H$\\sb2$- and dithionite-reduced forms of the methyl viologen-reducing hydrogenase are presented. These studies provide the first direct spectroscopic evidence of the presence of S $>$ ${1\\over2}$ (4Fe-4S) $\\sp{1+}$ clusters in the reduced enzyme as well as suggest a spin interaction between these clusters and the nickel site.","Made available in DSpace on 2011-05-07T13:27:56Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9021693.pdf: 11155291 bytes, checksum: c539988db74d70d1e2d0ea08aebc47e0 (MD5) Previous issue date: 1990","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:55:06Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:25:39-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission","ETDs are only available to UIUC Users without author permission","U of I Only"],"dc:identifier":["AAI9021693","(UMI)AAI9021693","http://hdl.handle.net/2142/22068"],"dc:language":["eng"],"dc:rights":["Copyright 1990 Hamilton, Cristi Lynn"],"dc:subject":["Chemistry, Analytical","Chemistry, Inorganic","Biophysics, General"],"dc:title":["The F(430) cofactor of methyl coenzyme M reductase: Ligand binding to the nickel and chemical modification of the tetrapyrrole substituents"],"dc:type":["text"],"thesis:degree_discipline":["Chemistry"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:25:19Z"}