{"id":{"repo_id":"unt","oai_identifier":"info:ark/67531/metadc3163"},"canonical_url":"https://search.dev.ndltd.org/etd/unt/info:ark/67531/metadc3163","repository":{"repo_id":"unt","name":"University of North Texas","base_url":"https://digital.library.unt.edu/oai/"},"display":{"title":"Effector Response of the Aspartate Transcarbamoylase From Wild Type Pseudomonas Putida and a Mutant with 11 Amino Acids Deleted at the N-terminus of PyrB.","abstract":"Like its enteric counterpart, aspartate transcarbamoylase (ATCase) from Pseudomonas putida is a dodecamer of two different polypeptides. Unlike the enterics, the Pseudomonas ATCase lacks regulatory polypeptides but employs instead inactive dihydroorotases for an active dodecamer. Previous work showed that PyrB contains not only the active site but also the effector binding sites for ATP, UTP and CTP at its N-terminus. In this work, 11 amino acids were deleted from the N-terminus of PyrB and the ATCase with the truncated protein was expressed in E. coli pyrB- and purified. The wild type enzyme was similarly treated. Velocity-substrate plots without effectors gave Michaelis-Menten kinetics in all cases. Deleting 11 amino acids did not affect dodecameric assembly but altered effector responses. When carbamoylphosphate was varied, the mutant enzyme was inhibited by UTP while the wild type enzyme was activated 2-fold. When the aspartate was varied, CTP had no effect on the mutant enzyme but strongly inhibited the wild type enzyme.","abstract_html":"Like its enteric counterpart, aspartate transcarbamoylase (ATCase) from Pseudomonas putida is a dodecamer of two different polypeptides. Unlike the enterics, the Pseudomonas ATCase lacks regulatory polypeptides but employs instead inactive dihydroorotases for an active dodecamer. Previous work showed that PyrB contains not only the active site but also the effector binding sites for ATP, UTP and CTP at its N-terminus. In this work, 11 amino acids were deleted from the N-terminus of PyrB and the ATCase with the truncated protein was expressed in E. coli pyrB- and purified. The wild type enzyme was similarly treated. Velocity-substrate plots without effectors gave Michaelis-Menten kinetics in all cases. Deleting 11 amino acids did not affect dodecameric assembly but altered effector responses. When carbamoylphosphate was varied, the mutant enzyme was inhibited by UTP while the wild type enzyme was activated 2-fold. When the aspartate was varied, CTP had no effect on the mutant enzyme but strongly inhibited the wild type enzyme.","abstract_has_math":false,"creators":["Asfour, Hani"],"institution":"University of North Texas","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":["O'Donovan, Gerard A.","Farinha, Mark A.","Benjamin, Robert C."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2002,"date_issued":"2002-05","date_published":"2002-05","updated_at":"2026-07-24T05:34:52Z","subjects":["Pyrimidine nucleotides -- Metabolism.","Pseudomonas.","UTP","dodecamer","ATCase","ATP","pyrimidine pathway"],"languages":["English"],"rights":["Public","Copyright","Asfour, Hani","Copyright is held by the author, unless otherwise noted. All rights reserved."],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["oclc: 54829013","https://digital.library.unt.edu/ark:/67531/metadc3163/","ark: ark:/67531/metadc3163"],"render_values":[{"text":"oclc: 54829013","href":null,"code":true},{"text":"https://digital.library.unt.edu/ark:/67531/metadc3163/","href":"https://digital.library.unt.edu/ark:/67531/metadc3163/","code":true},{"text":"ark: ark:/67531/metadc3163","href":null,"code":true}]}]},"links":{"outbound_url":"https://doi.org/10.12794/metadc3163","outbound_label":"DOI","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["O'Donovan, Gerard A.","Farinha, Mark A.","Benjamin, Robert C."]},{"key":"dc:creator","label":"Author","values":["Asfour, Hani"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2002-05"]},{"key":"dc:publisher","label":"Institution","values":["University of North Texas"]},{"key":"dc:type","label":"Dc Type","values":["Thesis or Dissertation"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Pyrimidine nucleotides -- Metabolism.","Pseudomonas.","UTP","dodecamer","ATCase","ATP","pyrimidine pathway"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["English"]},{"key":"dc:rights","label":"Dc Rights","values":["Public","Copyright","Asfour, Hani","Copyright is held by the author, unless otherwise noted. All rights reserved."]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["oclc: 54829013","doi: 10.12794/metadc3163","https://digital.library.unt.edu/ark:/67531/metadc3163/","ark: ark:/67531/metadc3163"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Like its enteric counterpart, aspartate transcarbamoylase (ATCase) from Pseudomonas putida is a dodecamer of two different polypeptides. Unlike the enterics, the Pseudomonas ATCase lacks regulatory polypeptides but employs instead inactive dihydroorotases for an active dodecamer. Previous work showed that PyrB contains not only the active site but also the effector binding sites for ATP, UTP and CTP at its N-terminus. In this work, 11 amino acids were deleted from the N-terminus of PyrB and the ATCase with the truncated protein was expressed in E. coli pyrB- and purified. The wild type enzyme was similarly treated. Velocity-substrate plots without effectors gave Michaelis-Menten kinetics in all cases. Deleting 11 amino acids did not affect dodecameric assembly but altered effector responses. When carbamoylphosphate was varied, the mutant enzyme was inhibited by UTP while the wild type enzyme was activated 2-fold. When the aspartate was varied, CTP had no effect on the mutant enzyme but strongly inhibited the wild type enzyme."]},{"key":"dc:format","label":"Dc Format","values":["Text"]},{"key":"dc:title","label":"Title","values":["Effector Response of the Aspartate Transcarbamoylase From Wild Type Pseudomonas Putida and a Mutant with 11 Amino Acids Deleted at the N-terminus of PyrB."]}]}],"canonical_facts":{"dc:contributor":["O'Donovan, Gerard A.","Farinha, Mark A.","Benjamin, Robert C."],"dc:creator":["Asfour, Hani"],"dc:date":["2002-05"],"dc:description":["Like its enteric counterpart, aspartate transcarbamoylase (ATCase) from Pseudomonas putida is a dodecamer of two different polypeptides. Unlike the enterics, the Pseudomonas ATCase lacks regulatory polypeptides but employs instead inactive dihydroorotases for an active dodecamer. Previous work showed that PyrB contains not only the active site but also the effector binding sites for ATP, UTP and CTP at its N-terminus. In this work, 11 amino acids were deleted from the N-terminus of PyrB and the ATCase with the truncated protein was expressed in E. coli pyrB- and purified. The wild type enzyme was similarly treated. Velocity-substrate plots without effectors gave Michaelis-Menten kinetics in all cases. Deleting 11 amino acids did not affect dodecameric assembly but altered effector responses. When carbamoylphosphate was varied, the mutant enzyme was inhibited by UTP while the wild type enzyme was activated 2-fold. When the aspartate was varied, CTP had no effect on the mutant enzyme but strongly inhibited the wild type enzyme."],"dc:format":["Text"],"dc:identifier":["oclc: 54829013","doi: 10.12794/metadc3163","https://digital.library.unt.edu/ark:/67531/metadc3163/","ark: ark:/67531/metadc3163"],"dc:language":["English"],"dc:publisher":["University of North Texas"],"dc:rights":["Public","Copyright","Asfour, Hani","Copyright is held by the author, unless otherwise noted. All rights reserved."],"dc:subject":["Pyrimidine nucleotides -- Metabolism.","Pseudomonas.","UTP","dodecamer","ATCase","ATP","pyrimidine pathway"],"dc:title":["Effector Response of the Aspartate Transcarbamoylase From Wild Type Pseudomonas Putida and a Mutant with 11 Amino Acids Deleted at the N-terminus of PyrB."],"dc:type":["Thesis or Dissertation"]},"updated_at":"2026-07-24T05:34:52Z"}