{"id":{"repo_id":"arizona-thes","oai_identifier":"oai:repository.arizona.edu:10150/204334"},"canonical_url":"https://search.dev.ndltd.org/etd/arizona-thes/oai:repository.arizona.edu:10150/204334","repository":{"repo_id":"arizona-thes","name":"University of Arizona","base_url":"https://repository.arizona.edu/oai/request"},"display":{"title":"Elucidation of the Biosynthetic Pathway for 7-Deazapurines","abstract":"Small molecules containing a 7-deazapurine moiety are ubiquitous in nature. They comprise a broad range of structurally diverse antibiotics produced by terrestrial and marine microorganisms that possess demonstrated antibiotic and antineoplastic activity. In addition, queuosine, a hypermodified nucleoside located in the wobble position of select tRNAs that is almost universally conserved throughout biology, contains a 7-deazapurine functional group. The since their initial identification over 50 years ago, the chemical transformations underlying the biosynthesis of 7-deazapurines have remained elusive. This work describes the identification of a cluster of co-localized genes in the Streptomyces rimosus chromosome that are responsible for the biosynthesis of the 7-deazapurine containing antibiotics toyocamycin and sangivamycin. Further, the in vitro conversion of GTP to the previously identified queuosine biosynthetic intermediate 7-cyano-7-deazaguanine (preQ₀) is demonstrated using purified, recombinant enzymes. Also included herein is a kinetic, spectroscopic, and mechanistic characterization of QueE, an enzyme that catalyzes the third step in the biosynthesis of 7-deazapurines using a radical-mediated rearrangement. A possible mechanism for the reaction catalyzed by QueD, the second step in the deazapurine biosynthetic pathway, is explored based on X-ray crystallographic data of site directed QueD mutants containing bound substrate. Finally, hitherto unrecognized gene clusters that are likely devoted to the biosynthesis of 7-deazapurines other than queuosine are described.","abstract_html":"Small molecules containing a 7-deazapurine moiety are ubiquitous in nature. They comprise a broad range of structurally diverse antibiotics produced by terrestrial and marine microorganisms that possess demonstrated antibiotic and antineoplastic activity. In addition, queuosine, a hypermodified nucleoside located in the wobble position of select tRNAs that is almost universally conserved throughout biology, contains a 7-deazapurine functional group. The since their initial identification over 50 years ago, the chemical transformations underlying the biosynthesis of 7-deazapurines have remained elusive. This work describes the identification of a cluster of co-localized genes in the Streptomyces rimosus chromosome that are responsible for the biosynthesis of the 7-deazapurine containing antibiotics toyocamycin and sangivamycin. Further, the in vitro conversion of GTP to the previously identified queuosine biosynthetic intermediate 7-cyano-7-deazaguanine (preQ₀) is demonstrated using purified, recombinant enzymes. Also included herein is a kinetic, spectroscopic, and mechanistic characterization of QueE, an enzyme that catalyzes the third step in the biosynthesis of 7-deazapurines using a radical-mediated rearrangement. A possible mechanism for the reaction catalyzed by QueD, the second step in the deazapurine biosynthetic pathway, is explored based on X-ray crystallographic data of site directed QueD mutants containing bound substrate. Finally, hitherto unrecognized gene clusters that are likely devoted to the biosynthesis of 7-deazapurines other than queuosine are described.","abstract_has_math":false,"creators":["McCarty, Reid Michael"],"institution":"The University of Arizona.","degree_name":"Ph.D.","degree_level":"doctoral","degree_discipline":"Graduate College","degree_department":null,"school":null,"contributors":[],"advisors":["Bandarian, Vahe"],"committee_chairs":[],"committee_members":["Cordes, Matthew H.","Molnar, Istvan","McEvoy, Megan M."],"year":2011,"date_issued":"2011","date_published":"2011","updated_at":"2026-07-24T00:57:45Z","subjects":["antibiotics","enzymology","natural products","tRNA"],"languages":["en"],"rights":["Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author."],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/10150/204334","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Bandarian, Vahe"]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Cordes, Matthew H.","Molnar, Istvan","McEvoy, Megan M."]},{"key":"dc:creator","label":"Author","values":["McCarty, Reid Michael"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2012-01-23T21:19:17Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2012-01-23T21:19:17Z"]},{"key":"dc:date.issued","label":"Date","values":["2011"]},{"key":"dc:publisher","label":"Institution","values":["The University of Arizona."]},{"key":"dc:type","label":"Dc Type","values":["text","Electronic Dissertation"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Graduate College","Biochemistry"]},{"key":"thesis:degree_level","label":"Degree Level","values":["doctoral"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Arizona"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["antibiotics","enzymology","natural products","tRNA"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author."]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/10150/204334"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Small molecules containing a 7-deazapurine moiety are ubiquitous in nature. They comprise a broad range of structurally diverse antibiotics produced by terrestrial and marine microorganisms that possess demonstrated antibiotic and antineoplastic activity. In addition, queuosine, a hypermodified nucleoside located in the wobble position of select tRNAs that is almost universally conserved throughout biology, contains a 7-deazapurine functional group. The since their initial identification over 50 years ago, the chemical transformations underlying the biosynthesis of 7-deazapurines have remained elusive. This work describes the identification of a cluster of co-localized genes in the Streptomyces rimosus chromosome that are responsible for the biosynthesis of the 7-deazapurine containing antibiotics toyocamycin and sangivamycin. Further, the in vitro conversion of GTP to the previously identified queuosine biosynthetic intermediate 7-cyano-7-deazaguanine (preQ₀) is demonstrated using purified, recombinant enzymes. Also included herein is a kinetic, spectroscopic, and mechanistic characterization of QueE, an enzyme that catalyzes the third step in the biosynthesis of 7-deazapurines using a radical-mediated rearrangement. A possible mechanism for the reaction catalyzed by QueD, the second step in the deazapurine biosynthetic pathway, is explored based on X-ray crystallographic data of site directed QueD mutants containing bound substrate. Finally, hitherto unrecognized gene clusters that are likely devoted to the biosynthesis of 7-deazapurines other than queuosine are described."]},{"key":"dc:title","label":"Title","values":["Elucidation of the Biosynthetic Pathway for 7-Deazapurines"]}]}],"canonical_facts":{"dc:contributor.advisor":["Bandarian, Vahe"],"dc:contributor.committeemember":["Cordes, Matthew H.","Molnar, Istvan","McEvoy, Megan M."],"dc:creator":["McCarty, Reid Michael"],"dc:date.accessioned":["2012-01-23T21:19:17Z"],"dc:date.available":["2012-01-23T21:19:17Z"],"dc:date.issued":["2011"],"dc:description.abstract":["Small molecules containing a 7-deazapurine moiety are ubiquitous in nature. They comprise a broad range of structurally diverse antibiotics produced by terrestrial and marine microorganisms that possess demonstrated antibiotic and antineoplastic activity. In addition, queuosine, a hypermodified nucleoside located in the wobble position of select tRNAs that is almost universally conserved throughout biology, contains a 7-deazapurine functional group. The since their initial identification over 50 years ago, the chemical transformations underlying the biosynthesis of 7-deazapurines have remained elusive. This work describes the identification of a cluster of co-localized genes in the Streptomyces rimosus chromosome that are responsible for the biosynthesis of the 7-deazapurine containing antibiotics toyocamycin and sangivamycin. Further, the in vitro conversion of GTP to the previously identified queuosine biosynthetic intermediate 7-cyano-7-deazaguanine (preQ₀) is demonstrated using purified, recombinant enzymes. Also included herein is a kinetic, spectroscopic, and mechanistic characterization of QueE, an enzyme that catalyzes the third step in the biosynthesis of 7-deazapurines using a radical-mediated rearrangement. A possible mechanism for the reaction catalyzed by QueD, the second step in the deazapurine biosynthetic pathway, is explored based on X-ray crystallographic data of site directed QueD mutants containing bound substrate. Finally, hitherto unrecognized gene clusters that are likely devoted to the biosynthesis of 7-deazapurines other than queuosine are described."],"dc:identifier.uri":["http://hdl.handle.net/10150/204334"],"dc:language.iso":["en"],"dc:publisher":["The University of Arizona."],"dc:rights":["Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author."],"dc:subject":["antibiotics","enzymology","natural products","tRNA"],"dc:title":["Elucidation of the Biosynthetic Pathway for 7-Deazapurines"],"dc:type":["text","Electronic Dissertation"],"thesis:degree_discipline":["Graduate College","Biochemistry"],"thesis:degree_level":["doctoral"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Arizona"]},"updated_at":"2026-07-24T00:57:45Z"}