{"doi":"10.1128/jb.136.1.219-226.1978","title":"Effect of Tryptophan Analogs on Derepression of the\n            <i>Escherichia coli</i>\n            Tryptophan Operon by Indole-3-Propionic Acid","abstract":"<jats:p>\n            The abilities of 14 tryptophan analogs to repress the tryptophan (\n            <jats:italic>trp</jats:italic>\n            ) operon have been studied in\n            <jats:italic>Escherichia coli</jats:italic>\n            cells derepressed by incubation with 0.25 mM indole-3-propionic acid (IPA).\n            <jats:italic>trp</jats:italic>\n            operon expression was monitored by measuring the specific activities of anthranilate synthase (EC 4.1.3.27) and the tryptophan synthase (EC 4.2.1.20) β subunit. Analogs characterized by modification or removal of the α-amino group or the α-carboxyl group did not repress the\n            <jats:italic>trp</jats:italic>\n            operon. The only analogs among this group that appeared to interact with the\n            <jats:italic>trp</jats:italic>\n            aporepressor were IPA, which derepressed the\n            <jats:italic>trp</jats:italic>\n            operon, and\n            <jats:sc>d</jats:sc>\n            -tryptophan. Analogs with modifications of the indole ring repressed the\n            <jats:italic>trp</jats:italic>\n            operon to various degrees. 7-Methyl-tryptophan inhibited anthranilate synthase activity and consequently derepressed the\n            <jats:italic>trp</jats:italic>\n            operon. Additionally, 7-methyltryptophan prevented IPA-mediated derepression but, unlike tryptophan, did so in a non-coordinate manner, with the later enzymes of the operon being relatively more repressed than the early enzymes. The effect of 7-methyltryptophan on IPA-mediated derepression was likely not due to the interaction of IPA with the allosteric site of anthranilate synthase, even though feedback-resistant mutants of anthranilate synthase were partially resistant to derepression by IPA. The effect of 7-methyltryptophan on derepression by IPA was probably due to the effect of the analog-aporepressor complex on\n            <jats:italic>trp</jats:italic>\n            operon expression.\n          </jats:p>","journal":"Journal of Bacteriology","year":1978,"id":16291,"datarank":1.3871109666831505,"base_score":2.639057329615259,"endowment":2.639057329615259,"self_citation_contribution":0.3958585994422889,"citation_network_contribution":0.9912523672408615,"self_endowment_contribution":0.3958585994422889,"citer_contribution":0.9912523672408615,"corpus_percentile":null,"corpus_rank":null,"citation_count":13,"citer_count":13,"citers_with_citation_signal":13,"citers_with_endowment":13,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":null,"is_oa":false,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":null,"fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":120796,"name":"Walter W. Fredricks","orcid":null,"position":1,"is_corresponding":false},{"id":120797,"name":"Oliver H. Smith","orcid":null,"position":2,"is_corresponding":false},{"id":120795,"name":"Robert J. Pauley","orcid":null,"position":0,"is_corresponding":false}],"reference_count":0,"raw_metadata":{"has_enrichment":true,"base_score":2.639057329615259,"endowment":2.639057329615259,"datacite_reuse_total":0,"file_count":0,"downloads":0,"views":0,"has_version_chain":false,"is_dataset":false,"is_oa":false,"pmid":"361689","pmcid":"PMC218652","openalex_id":"https://openalex.org/W1918886864","authors":[],"funders":[],"total_grants":0,"fwci":0.2035,"citation_percentile":0.44866364,"influential_citations":0,"citation_trend":[{"year":2015,"count":1},{"year":2020,"count":1},{"year":2022,"count":1},{"year":2023,"count":1},{"year":2024,"count":1}],"oa_status":"bronze","license":"https://journals.asm.org/non-commercial-tdm-license","oa_locations":[{"url":"https://jb.asm.org/content/jb/136/1/219.full.pdf","host_type":"journal"},{"url":"https://jb.asm.org/content/jb/136/1/219.full.pdf","host_type":"BRONZE"},{"url":"https://jb.asm.org/content/jb/136/1/219.full.pdf","host_type":"publisher"},{"url":"https://journals.asm.org/doi/pdf/10.1128/jb.136.1.219-226.1978","host_type":"publisher"},{"url":"https://doi.org/10.1128/jb.136.1.219-226.1978","host_type":"journal"},{"url":"https://pubmed.ncbi.nlm.nih.gov/361689","host_type":"repository"},{"url":"https://epublications.marquette.edu/biomedsci_fac/101","host_type":"repository"},{"url":"http://europepmc.org/pmc/articles/PMC218652","host_type":"repository"},{"url":"https://www.ncbi.nlm.nih.gov/pmc/articles/218652","host_type":"repository"}],"fields_of_study":["Biochemical and Molecular Research","Microbial Metabolic Engineering and Bioproduction","Fungal and yeast genetics research","Biology","Medicine","Chemistry","Anthranilate Synthase","Enzyme Repression","Escherichia coli","Operon","Structure-Activity Relationship","Tryptophan","Tryptophan Synthase"],"mesh_terms":["Anthranilate Synthase","Enzyme Repression","Escherichia coli","Operon","Structure-Activity Relationship","Tryptophan","Tryptophan Synthase"],"keywords":["Derepression","Tryptophan synthase","trp operon","Operon","Tryptophan","gal operon","Biology","L-arabinose operon","Biochemistry","Escherichia coli","Enzyme","Indole test","Enzyme Repression","Amino acid","Gene","Gene expression","Psychological repression"],"sdg_mappings":[],"linked_datasets":[],"clinical_trials":[],"software_tools":[],"database_accessions":[],"source":"live","citation_network_status":"fetched"},"created_at":"2026-06-01T21:16:05.330631Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}