{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/77685"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/77685","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"The Mechanism of Chloride Activation of Oxygen Evolution in Spinach Photosystem Ii","abstract":"The mechanism by which ${\\rm Cl}\\sp-$ activates the oxygen-evolving complex (OEC) of Photosystem II (PS II) was studied by $\\sp{35}{\\rm Cl}$-NMR and steady-state measurements of oxygen evolution. This study represents the first attempt to directly monitor ${\\rm Cl}\\sp-$ binding in spinach. At low light intensity, the ${\\rm Cl}\\sp-$ activation curve (Hill activity vs. (${\\rm Cl}\\sp-$)) shows three intermediary plateaus in the concentration range 0.1-10 mM ${\\rm Cl}\\sp-,$ indicating kinetic cooperativity with respect to ${\\rm Cl}\\sp-.$ The $\\sp{35}{\\rm Cl}$-NMR binding curve (excess linewidth vs. (${\\rm Cl}\\sp-$)) for ${\\rm Cl}\\sp-$ depleted thylakoids and PS II membranes is not a smoothly descending hyperbola. Instead, this curve shows four sharp increases in linewidth (linewidth maxima) in the concentration range 0.1-10 mM ${\\rm Cl}\\sp-.$ The presence of these linewidth maxima indicates that ${\\rm Cl}\\sp-$ addition exposes four ${\\rm Cl}\\sp-$ binding sites that were not previously accessible to exchange. The pH-dependence for the excess linewidth at 0.75 mM ${\\rm Cl}\\sp-$ shows a maximum at pH 6.0 and two smaller maxima at pH 5.4 and 6.5. Mild heating eliminates both the linewidth maxima and the plateaus in the ${\\rm Cl}\\sp-$ activation curve. Hydroxylamine treatment (1.5 mM) has little effect on ${\\rm Cl}\\sp-$ binding, indicating that Mn is not involved. Tris-washing eliminates nearly all of the high-affinity ${\\rm Cl}\\sp-$ binding. Measurements of PS II membranes washed with 1.0 M NaCl or ${\\rm CaCl}\\sb2$ indicate that the native ${\\rm Cl}\\sp-$ binding mechanism requires the presence of the 33 kD extrinsic polypeptide, but that the function of the 18 kD and 24 kD extrinsic polypeptides can be replaced by 2.0 mM ${\\rm Ca}\\sp{2+}.$ Chloride binding is still observed after removal of all three extrinsic polypeptides, but the $\\sp{35}{\\rm Cl}$-NMR binding curve shows only a single, broad linewidth maximum at about 0.5 mM ${\\rm Cl}\\sp-.$ A hypothetical model is proposed to explain these results. This model involves ${\\rm Cl}\\sp-$ binding at two types of sites: (1) an intrinsic site (composed of three histidines) on the D1/D2 proteins, and (2) a set of four extrinsic sites (composed of lysines and arginines) on the 33 kD polypeptide. Possible amino acid ligands for the tetra-nuclear Mn cluster (on D1/D2) are also described.","abstract_html":"The mechanism by which ${\\rm Cl}\\sp-$ activates the oxygen-evolving complex (OEC) of Photosystem II (PS II) was studied by $\\sp{35}{\\rm Cl}$-NMR and steady-state measurements of oxygen evolution. This study represents the first attempt to directly monitor ${\\rm Cl}\\sp-$ binding in spinach. At low light intensity, the ${\\rm Cl}\\sp-$ activation curve (Hill activity vs. (${\\rm Cl}\\sp-$)) shows three intermediary plateaus in the concentration range 0.1-10 mM ${\\rm Cl}\\sp-,$ indicating kinetic cooperativity with respect to ${\\rm Cl}\\sp-.$ The $\\sp{35}{\\rm Cl}$-NMR binding curve (excess linewidth vs. (${\\rm Cl}\\sp-$)) for ${\\rm Cl}\\sp-$ depleted thylakoids and PS II membranes is not a smoothly descending hyperbola. Instead, this curve shows four sharp increases in linewidth (linewidth maxima) in the concentration range 0.1-10 mM ${\\rm Cl}\\sp-.$ The presence of these linewidth maxima indicates that ${\\rm Cl}\\sp-$ addition exposes four ${\\rm Cl}\\sp-$ binding sites that were not previously accessible to exchange. The pH-dependence for the excess linewidth at 0.75 mM ${\\rm Cl}\\sp-$ shows a maximum at pH 6.0 and two smaller maxima at pH 5.4 and 6.5. Mild heating eliminates both the linewidth maxima and the plateaus in the ${\\rm Cl}\\sp-$ activation curve. Hydroxylamine treatment (1.5 mM) has little effect on ${\\rm Cl}\\sp-$ binding, indicating that Mn is not involved. Tris-washing eliminates nearly all of the high-affinity ${\\rm Cl}\\sp-$ binding. Measurements of PS II membranes washed with 1.0 M NaCl or ${\\rm CaCl}\\sb2$ indicate that the native ${\\rm Cl}\\sp-$ binding mechanism requires the presence of the 33 kD extrinsic polypeptide, but that the function of the 18 kD and 24 kD extrinsic polypeptides can be replaced by 2.0 mM ${\\rm Ca}\\sp{2+}.$ Chloride binding is still observed after removal of all three extrinsic polypeptides, but the $\\sp{35}{\\rm Cl}$-NMR binding curve shows only a single, broad linewidth maximum at about 0.5 mM ${\\rm Cl}\\sp-.$ A hypothetical model is proposed to explain these results. This model involves ${\\rm Cl}\\sp-$ binding at two types of sites: (1) an intrinsic site (composed of three histidines) on the D1/D2 proteins, and (2) a set of four extrinsic sites (composed of lysines and arginines) on the 33 kD polypeptide. Possible amino acid ligands for the tetra-nuclear Mn cluster (on D1/D2) are also described.","abstract_has_math":true,"creators":["Coleman, William Joseph"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Biochemistry","degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2015,"date_issued":"2015-05-14T15:21:26Z","date_published":"2015-05-14T15:21:26Z","updated_at":"2026-07-22T22:26:11Z","subjects":["Chemistry, Biochemistry"],"languages":["eng"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["(UMI)AAI8721614"],"render_values":[{"text":"(UMI)AAI8721614","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/77685","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Coleman, William Joseph"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2015-05-14T15:21:26Z","10000-01-01","1987"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Biochemistry"]},{"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":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/77685","(UMI)AAI8721614"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["The mechanism by which ${\\rm Cl}\\sp-$ activates the oxygen-evolving complex (OEC) of Photosystem II (PS II) was studied by $\\sp{35}{\\rm Cl}$-NMR and steady-state measurements of oxygen evolution. This study represents the first attempt to directly monitor ${\\rm Cl}\\sp-$ binding in spinach. At low light intensity, the ${\\rm Cl}\\sp-$ activation curve (Hill activity vs. (${\\rm Cl}\\sp-$)) shows three intermediary plateaus in the concentration range 0.1-10 mM ${\\rm Cl}\\sp-,$ indicating kinetic cooperativity with respect to ${\\rm Cl}\\sp-.$ The $\\sp{35}{\\rm Cl}$-NMR binding curve (excess linewidth vs. (${\\rm Cl}\\sp-$)) for ${\\rm Cl}\\sp-$ depleted thylakoids and PS II membranes is not a smoothly descending hyperbola. Instead, this curve shows four sharp increases in linewidth (linewidth maxima) in the concentration range 0.1-10 mM ${\\rm Cl}\\sp-.$ The presence of these linewidth maxima indicates that ${\\rm Cl}\\sp-$ addition exposes four ${\\rm Cl}\\sp-$ binding sites that were not previously accessible to exchange. The pH-dependence for the excess linewidth at 0.75 mM ${\\rm Cl}\\sp-$ shows a maximum at pH 6.0 and two smaller maxima at pH 5.4 and 6.5. Mild heating eliminates both the linewidth maxima and the plateaus in the ${\\rm Cl}\\sp-$ activation curve. Hydroxylamine treatment (1.5 mM) has little effect on ${\\rm Cl}\\sp-$ binding, indicating that Mn is not involved. Tris-washing eliminates nearly all of the high-affinity ${\\rm Cl}\\sp-$ binding. Measurements of PS II membranes washed with 1.0 M NaCl or ${\\rm CaCl}\\sb2$ indicate that the native ${\\rm Cl}\\sp-$ binding mechanism requires the presence of the 33 kD extrinsic polypeptide, but that the function of the 18 kD and 24 kD extrinsic polypeptides can be replaced by 2.0 mM ${\\rm Ca}\\sp{2+}.$ Chloride binding is still observed after removal of all three extrinsic polypeptides, but the $\\sp{35}{\\rm Cl}$-NMR binding curve shows only a single, broad linewidth maximum at about 0.5 mM ${\\rm Cl}\\sp-.$ A hypothetical model is proposed to explain these results. This model involves ${\\rm Cl}\\sp-$ binding at two types of sites: (1) an intrinsic site (composed of three histidines) on the D1/D2 proteins, and (2) a set of four extrinsic sites (composed of lysines and arginines) on the 33 kD polypeptide. Possible amino acid ligands for the tetra-nuclear Mn cluster (on D1/D2) are also described.","Made available in DSpace on 2015-05-14T15:21:26Z (GMT). No. of bitstreams: 2 license.txt: 4848 bytes, checksum: 96035ab3f5e1c23cc7138a224ce498bd (MD5) 8721614.PDF: 5906634 bytes, checksum: 11528a5ebf1f90e9553f740a57a66020 (MD5) Previous issue date: 1987","Embargo set by: Seth Robbins for item 78895 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","222 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1987."]},{"key":"dc:title","label":"Title","values":["The Mechanism of Chloride Activation of Oxygen Evolution in Spinach Photosystem Ii"]}]}],"canonical_facts":{"dc:creator":["Coleman, William Joseph"],"dc:date":["2015-05-14T15:21:26Z","10000-01-01","1987"],"dc:description":["The mechanism by which ${\\rm Cl}\\sp-$ activates the oxygen-evolving complex (OEC) of Photosystem II (PS II) was studied by $\\sp{35}{\\rm Cl}$-NMR and steady-state measurements of oxygen evolution. This study represents the first attempt to directly monitor ${\\rm Cl}\\sp-$ binding in spinach. At low light intensity, the ${\\rm Cl}\\sp-$ activation curve (Hill activity vs. (${\\rm Cl}\\sp-$)) shows three intermediary plateaus in the concentration range 0.1-10 mM ${\\rm Cl}\\sp-,$ indicating kinetic cooperativity with respect to ${\\rm Cl}\\sp-.$ The $\\sp{35}{\\rm Cl}$-NMR binding curve (excess linewidth vs. (${\\rm Cl}\\sp-$)) for ${\\rm Cl}\\sp-$ depleted thylakoids and PS II membranes is not a smoothly descending hyperbola. Instead, this curve shows four sharp increases in linewidth (linewidth maxima) in the concentration range 0.1-10 mM ${\\rm Cl}\\sp-.$ The presence of these linewidth maxima indicates that ${\\rm Cl}\\sp-$ addition exposes four ${\\rm Cl}\\sp-$ binding sites that were not previously accessible to exchange. The pH-dependence for the excess linewidth at 0.75 mM ${\\rm Cl}\\sp-$ shows a maximum at pH 6.0 and two smaller maxima at pH 5.4 and 6.5. Mild heating eliminates both the linewidth maxima and the plateaus in the ${\\rm Cl}\\sp-$ activation curve. Hydroxylamine treatment (1.5 mM) has little effect on ${\\rm Cl}\\sp-$ binding, indicating that Mn is not involved. Tris-washing eliminates nearly all of the high-affinity ${\\rm Cl}\\sp-$ binding. Measurements of PS II membranes washed with 1.0 M NaCl or ${\\rm CaCl}\\sb2$ indicate that the native ${\\rm Cl}\\sp-$ binding mechanism requires the presence of the 33 kD extrinsic polypeptide, but that the function of the 18 kD and 24 kD extrinsic polypeptides can be replaced by 2.0 mM ${\\rm Ca}\\sp{2+}.$ Chloride binding is still observed after removal of all three extrinsic polypeptides, but the $\\sp{35}{\\rm Cl}$-NMR binding curve shows only a single, broad linewidth maximum at about 0.5 mM ${\\rm Cl}\\sp-.$ A hypothetical model is proposed to explain these results. This model involves ${\\rm Cl}\\sp-$ binding at two types of sites: (1) an intrinsic site (composed of three histidines) on the D1/D2 proteins, and (2) a set of four extrinsic sites (composed of lysines and arginines) on the 33 kD polypeptide. Possible amino acid ligands for the tetra-nuclear Mn cluster (on D1/D2) are also described.","Made available in DSpace on 2015-05-14T15:21:26Z (GMT). No. of bitstreams: 2 license.txt: 4848 bytes, checksum: 96035ab3f5e1c23cc7138a224ce498bd (MD5) 8721614.PDF: 5906634 bytes, checksum: 11528a5ebf1f90e9553f740a57a66020 (MD5) Previous issue date: 1987","Embargo set by: Seth Robbins for item 78895 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","222 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1987."],"dc:identifier":["http://hdl.handle.net/2142/77685","(UMI)AAI8721614"],"dc:language":["eng"],"dc:subject":["Chemistry, Biochemistry"],"dc:title":["The Mechanism of Chloride Activation of Oxygen Evolution in Spinach Photosystem Ii"],"dc:type":["text"],"thesis:degree_discipline":["Biochemistry"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:26:11Z"}