{"doi":"10.3390/ijms222413392","title":"X-ray Characterization of Conformational Changes of Human Apo- and Holo-Transferrin","abstract":"Human serum transferrin (Tf) is a bilobed glycoprotein whose function is to transport iron through receptor-mediated endocytosis. The mechanism for iron release is pH-dependent and involves conformational changes in the protein, thus making it an attractive system for possible biomedical applications. In this contribution, two powerful X-ray techniques, namely Macromolecular X-ray Crystallography (MX) and Small Angle X-ray Scattering (SAXS), were used to study the conformational changes of iron-free (apo) and iron-loaded (holo) transferrin in crystal and solution states, respectively, at three different pH values of physiological relevance. A crystallographic model of glycosylated apo-Tf was obtained at 3.0 Å resolution, which did not resolve further despite many efforts to improve crystal quality. In the solution, apo-Tf remained mostly globular in all the pH conditions tested; however, the co-existence of closed, partially open, and open conformations was observed for holo-Tf, which showed a more elongated and flexible shape overall.","journal":"International Journal of Molecular Sciences","year":2021,"id":190480,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":14,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9517,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2021-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":754658,"name":"Dritan Siliqi","orcid":"0000-0003-1415-8725","position":1,"is_corresponding":false},{"id":754659,"name":"Luis A. González-Ramírez","orcid":"0000-0001-9179-1140","position":2,"is_corresponding":false},{"id":754660,"name":"Carmen López‐Sánchez","orcid":"0000-0003-3296-2071","position":3,"is_corresponding":false},{"id":647862,"name":"Jose A. Gavira","orcid":"0000-0002-7386-6484","position":4,"is_corresponding":false},{"id":754661,"name":"Abel Moreno","orcid":"0000-0002-5810-078X","position":5,"is_corresponding":false},{"id":754657,"name":"Camila Campos-Escamilla","orcid":"0000-0002-7219-0494","position":0,"is_corresponding":true}],"reference_count":54,"raw_metadata":null,"created_at":"2026-07-18T23:49:26.966524Z","pmid":"34948188","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":[]}