{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/22447"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/22447","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Effects of amino acid residue substitutions on bicarbonate function in the plastoquinone reductase in cyanobacteria","abstract":"The electron transfer at the Q$\\sb{\\rm A}$FeQ$\\sb{\\rm B}$ complex is significantly and reversibly inhibited in chloroplasts of higher plants and algae depleted of bicarbonate while no such inhibition has been observed in photosynthetic bacteria. It was observed in this study that a more than four fold stimulation of the Hill reaction by 5 mM bicarbonate and a significant reversible slowing of oxidation of Q$\\sb{\\rm A}\\sp{-}$ in bicarbonate-depleted cells and thylakoids of Synechocystis sp. PCC 6803, showing the existence of the bicarbonate effect in cyanobacteria. Thus, this effect is present in all Photosystem II (PSII) reaction centers.","abstract_html":"The electron transfer at the Q$\\sb{\\rm A}$FeQ$\\sb{\\rm B}$ complex is significantly and reversibly inhibited in chloroplasts of higher plants and algae depleted of bicarbonate while no such inhibition has been observed in photosynthetic bacteria. It was observed in this study that a more than four fold stimulation of the Hill reaction by 5 mM bicarbonate and a significant reversible slowing of oxidation of Q$\\sb{\\rm A}\\sp{-}$ in bicarbonate-depleted cells and thylakoids of Synechocystis sp. PCC 6803, showing the existence of the bicarbonate effect in cyanobacteria. Thus, this effect is present in all Photosystem II (PSII) reaction centers.","abstract_has_math":true,"creators":["Cao, Jiancheng"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Biology","degree_department":null,"school":null,"contributors":["Govindjee"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-05-07T13:40:07Z","date_published":"2011-05-07T13:40:07Z","updated_at":"2026-07-22T22:25:20Z","subjects":["Biology, Molecular","Biology, Microbiology"],"languages":["eng"],"rights":["Copyright 1992 Cao, Jiancheng"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["AAI9215782","(UMI)AAI9215782"],"render_values":[{"text":"AAI9215782","href":null,"code":true},{"text":"(UMI)AAI9215782","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/22447","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Govindjee"]},{"key":"dc:creator","label":"Author","values":["Cao, Jiancheng"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011-05-07T13:40:07Z","10000-01-01","1992"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Biology"]},{"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":["Biology, Molecular","Biology, Microbiology"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 1992 Cao, Jiancheng"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["AAI9215782","(UMI)AAI9215782","http://hdl.handle.net/2142/22447"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["The electron transfer at the Q$\\sb{\\rm A}$FeQ$\\sb{\\rm B}$ complex is significantly and reversibly inhibited in chloroplasts of higher plants and algae depleted of bicarbonate while no such inhibition has been observed in photosynthetic bacteria. It was observed in this study that a more than four fold stimulation of the Hill reaction by 5 mM bicarbonate and a significant reversible slowing of oxidation of Q$\\sb{\\rm A}\\sp{-}$ in bicarbonate-depleted cells and thylakoids of Synechocystis sp. PCC 6803, showing the existence of the bicarbonate effect in cyanobacteria. Thus, this effect is present in all Photosystem II (PSII) reaction centers.","Oligonucleotide-directed mutagenesis was used to construct Synechocystis 6803 mutants carrying mutations in arginine residues in the D2 protein. Measurements of oxygen evolution showed that the D2 mutants D2-R233Q (arginine-233 $\\to$ glutamine) and D2-R251S (arginine-251 $\\to$ serine) were ten-fold more sensitive to formate, which displaces bicarbonate, than the wild type. Measurements of oxygen evolution in single-turnover flashes and chlorophyll (Chl) a fluorescence decay kinetics confirmed that D2-R251S and D2-R233Q are more sensitive than the wild type. It is suggested that the D2 protein is involved in the bicarbonate effect in PSII and the two arginine residues are important for the stabilization of bicarbonate binding in PSII.","The D1 protein of PSII is known to be involved in the bicarbonate effect. To examine the changes in the binding affinity of bicarbonate and formate in site-selected herbicide-resistant D1 mutants in Synechococcus sp. PCC 7942, a rapid equilibrium model involving activator-inhibitor interactions was used to estimate the dissociation constant for bicarbonate and for formate. The data indicated that these D1 mutations increase the dissociation constants for bicarbonate while those for formate are virtually unchanged. A working hypothesis is proposed in which bicarbonate forms a bidentate ligand to Fe$\\sp{2+}$ and participates in the proton transfer pathway to the formation of plastoquinol Q$\\sb{\\rm B}$H$\\sb2$ at the plastoquinone reductase.","Made available in DSpace on 2011-05-07T13:40:07Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9215782.pdf: 8613781 bytes, checksum: e4c9c544f38c0078958c923828e56cb7 (MD5) Previous issue date: 1992","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:57:41Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:27:04-05:00 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":["Effects of amino acid residue substitutions on bicarbonate function in the plastoquinone reductase in cyanobacteria"]}]}],"canonical_facts":{"dc:contributor":["Govindjee"],"dc:creator":["Cao, Jiancheng"],"dc:date":["2011-05-07T13:40:07Z","10000-01-01","1992"],"dc:description":["The electron transfer at the Q$\\sb{\\rm A}$FeQ$\\sb{\\rm B}$ complex is significantly and reversibly inhibited in chloroplasts of higher plants and algae depleted of bicarbonate while no such inhibition has been observed in photosynthetic bacteria. It was observed in this study that a more than four fold stimulation of the Hill reaction by 5 mM bicarbonate and a significant reversible slowing of oxidation of Q$\\sb{\\rm A}\\sp{-}$ in bicarbonate-depleted cells and thylakoids of Synechocystis sp. PCC 6803, showing the existence of the bicarbonate effect in cyanobacteria. Thus, this effect is present in all Photosystem II (PSII) reaction centers.","Oligonucleotide-directed mutagenesis was used to construct Synechocystis 6803 mutants carrying mutations in arginine residues in the D2 protein. Measurements of oxygen evolution showed that the D2 mutants D2-R233Q (arginine-233 $\\to$ glutamine) and D2-R251S (arginine-251 $\\to$ serine) were ten-fold more sensitive to formate, which displaces bicarbonate, than the wild type. Measurements of oxygen evolution in single-turnover flashes and chlorophyll (Chl) a fluorescence decay kinetics confirmed that D2-R251S and D2-R233Q are more sensitive than the wild type. It is suggested that the D2 protein is involved in the bicarbonate effect in PSII and the two arginine residues are important for the stabilization of bicarbonate binding in PSII.","The D1 protein of PSII is known to be involved in the bicarbonate effect. To examine the changes in the binding affinity of bicarbonate and formate in site-selected herbicide-resistant D1 mutants in Synechococcus sp. PCC 7942, a rapid equilibrium model involving activator-inhibitor interactions was used to estimate the dissociation constant for bicarbonate and for formate. The data indicated that these D1 mutations increase the dissociation constants for bicarbonate while those for formate are virtually unchanged. A working hypothesis is proposed in which bicarbonate forms a bidentate ligand to Fe$\\sp{2+}$ and participates in the proton transfer pathway to the formation of plastoquinol Q$\\sb{\\rm B}$H$\\sb2$ at the plastoquinone reductase.","Made available in DSpace on 2011-05-07T13:40:07Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9215782.pdf: 8613781 bytes, checksum: e4c9c544f38c0078958c923828e56cb7 (MD5) Previous issue date: 1992","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:57:41Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:27:04-05:00 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":["AAI9215782","(UMI)AAI9215782","http://hdl.handle.net/2142/22447"],"dc:language":["eng"],"dc:rights":["Copyright 1992 Cao, Jiancheng"],"dc:subject":["Biology, Molecular","Biology, Microbiology"],"dc:title":["Effects of amino acid residue substitutions on bicarbonate function in the plastoquinone reductase in cyanobacteria"],"dc:type":["text"],"thesis:degree_discipline":["Biology"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:25:20Z"}