{"doi":"10.1073/pnas.82.17.5905","title":"Secondary structure of the immunoglobulin J chain.","abstract":"<jats:p>J chain is a 137-residue polypeptide that is covalently linked to polymeric immunoglobulins and participates in their synthesis and transport to external secretions. To clarify these roles, the secondary structure of J chain was characterized by computer-assisted analyses of human and mouse sequences and by circular dichroism measurements of the isolated J chain. The secondary-structure profiles obtained were very similar to those of superoxide dismutase or immunoglobulin light chain variable domains, suggesting that the J chain folds into an eight-stranded antiparallel beta-barrel and should contain approximately 37% beta-sheet conformation, with the rest of the structure existing as reverse turns (random coil). The circular dichroism measurements indicated that the conformation of denatured, S-carboxymethylated or S-sulfonated J chain consists of 75% random coil and 25% beta-structure. Upon reformation of disulfide bonds the percentage of beta-structure in the air-oxidized J chain increased to 34%, a value that is in good agreement with the secondary-structure analysis. Two alternative models of J-chain structure, a two-domain model [Cann, G., Zaritsky, A. &amp; Koshland, M.E. (1982) Proc. Natl. Acad. Sci. USA 79, 6656-6660] and a single-domain antiparallel beta-sheet bilayer model (proposed in this paper), are compared.</jats:p>","journal":"Proceedings of the National Academy of Sciences","year":1985,"id":650144,"datarank":0.6141516843333151,"base_score":4.0943445622221,"endowment":4.0943445622221,"self_citation_contribution":0.6141516843333151,"citation_network_contribution":0.0,"self_endowment_contribution":0.6141516843333151,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":59,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":null,"is_data_producer":false,"deposit_databanks":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":1695126,"name":"J Novotny","orcid":null,"position":1,"is_corresponding":false},{"id":1695129,"name":"T L Trapane","orcid":null,"position":2,"is_corresponding":false},{"id":1695131,"name":"M E Koshland","orcid":null,"position":3,"is_corresponding":false},{"id":1695132,"name":"D W Urry","orcid":null,"position":4,"is_corresponding":false},{"id":1695134,"name":"J C Bennett","orcid":null,"position":5,"is_corresponding":false},{"id":1560806,"name":"J Mestecky","orcid":null,"position":6,"is_corresponding":false},{"id":1695123,"name":"J Zikan","orcid":null,"position":0,"is_corresponding":false}],"reference_count":0,"raw_metadata":{"has_enrichment":true,"resolved":true,"title":"Secondary structure of the immunoglobulin J chain.","abstract":"<jats:p>J chain is a 137-residue polypeptide that is covalently linked to polymeric immunoglobulins and participates in their synthesis and transport to external secretions. To clarify these roles, the secondary structure of J chain was characterized by computer-assisted analyses of human and mouse sequences and by circular dichroism measurements of the isolated J chain. The secondary-structure profiles obtained were very similar to those of superoxide dismutase or immunoglobulin light chain variable domains, suggesting that the J chain folds into an eight-stranded antiparallel beta-barrel and should contain approximately 37% beta-sheet conformation, with the rest of the structure existing as reverse turns (random coil). The circular dichroism measurements indicated that the conformation of denatured, S-carboxymethylated or S-sulfonated J chain consists of 75% random coil and 25% beta-structure. Upon reformation of disulfide bonds the percentage of beta-structure in the air-oxidized J chain increased to 34%, a value that is in good agreement with the secondary-structure analysis. Two alternative models of J-chain structure, a two-domain model [Cann, G., Zaritsky, A. &amp; Koshland, M.E. (1982) Proc. Natl. Acad. Sci. USA 79, 6656-6660] and a single-domain antiparallel beta-sheet bilayer model (proposed in this paper), are compared.</jats:p>","is_dataset_classified":null,"base_score":4.0943445622221,"endowment":4.0943445622221,"datacite_reuse_total":0,"file_count":0,"downloads":0,"views":0,"has_version_chain":false,"is_dataset":false,"is_oa":false,"pmid":"3929246","pmcid":"PMC390662","openalex_id":"https://openalex.org/W2046550930","authors":[],"funders":[{"funder_name":"NHLBI NIH HHS","grant_id":"HL29578","title":null},{"funder_name":"NIAID NIH HHS","grant_id":"AI10854","title":null}],"total_grants":2,"fwci":3.4406,"citation_percentile":0.92882504,"influential_citations":0,"citation_trend":[{"year":2012,"count":1},{"year":2013,"count":2},{"year":2014,"count":1},{"year":2015,"count":1},{"year":2017,"count":2},{"year":2018,"count":1},{"year":2020,"count":3},{"year":2022,"count":2},{"year":2023,"count":3}],"oa_status":"green","license":null,"oa_locations":[{"url":"https://www.ncbi.nlm.nih.gov/pmc/articles/390662","host_type":"repository"},{"url":"https://www.ncbi.nlm.nih.gov/pmc/articles/390662","host_type":"repository"},{"url":"https://pnas.org/doi/pdf/10.1073/pnas.82.17.5905","host_type":"publisher"},{"url":"https://doi.org/10.1073/pnas.82.17.5905","host_type":"journal"},{"url":"https://pubmed.ncbi.nlm.nih.gov/3929246","host_type":"repository"}],"fields_of_study":["Biochemical effects in animals","Protein Structure and Dynamics","Alcohol Consumption and Health Effects","Animals","Circular Dichroism","Disulfides","Humans","Hydrogen Bonding","Immunoglobulin J-Chains","Immunoglobulin Light Chains","Mice","Protein Conformation","Superoxide Dismutase"],"mesh_terms":["Animals","Circular Dichroism","Disulfides","Humans","Hydrogen Bonding","Immunoglobulin J-Chains","Immunoglobulin Light Chains","Protein Conformation","Superoxide Dismutase","Mice"],"keywords":["Antiparallel (mathematics)","Random coil","Protein secondary structure","Chemistry","Circular dichroism","J chain","Beta sheet","Immunoglobulin light chain","Protein structure","Covalent bond","Crystallography","Bilayer","Stereochemistry","Biophysics","Biochemistry","Antibody","Membrane","Biology","Physics"],"sdg_mappings":[{"sdg_number":0,"sdg_label":"Clean water and sanitation"}],"linked_datasets":[],"clinical_trials":[],"software_tools":[],"database_accessions":[],"source":"live","citation_network_status":"fetched"},"created_at":"2026-08-10T04:55:25.977327Z","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":[]}