{"doi":"10.1021/jacs.4c03916","title":"Deconvoluting Monomer- and Dimer-Specific Distance Distributions between Spin Labels in a Monomer/Dimer Mixture Using <i>T</i><sub>1</sub>-Edited DEER EPR Spectroscopy","abstract":"Double electron–electron resonance (DEER) EPR is a powerful tool in structural biology, providing distances between pairs of spin labels. When the sample consists of a mixture of oligomeric species (e.g., monomer and dimer), the question arises as to how to assign the peaks in the DEER-derived probability distance distribution to the individual species. Here, we propose incorporating an EPR longitudinal electron relaxation ( T 1 ) inversion recovery experiment within a DEER pulse sequence to resolve this problem. The apparent T 1 between dipolar coupled electron spins measured from the inversion recovery time (τ inv ) dependence of the peak intensities in the T 1 -edited DEER-derived probability P ( r ) distance distribution will be affected by the number of nitroxide labels attached to the biomolecule of interest, for example, two for a monomer and four for a dimer. We show that global fitting of all the T 1 -edited DEER echo curves, recorded over a range of τ inv values, permits the deconvolution of distances between spin labels originating from monomeric (longer T 1 ) and dimeric (shorter T 1 ) species. This is especially useful when the trapping of spin labels in different conformational states during freezing gives rise to complex P ( r ) distance distributions. The utility of this approach is demonstrated for two systems, the β 1 adrenergic receptor and a construct of the huntingtin exon-1 protein fused to the immunoglobulin domain of protein G, both of which exist in a monomer–dimer equilibrium.","journal":"Journal of the American Chemical Society","year":2024,"id":438553,"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":10,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9508,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2024-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":977105,"name":"Nina Kubatova","orcid":null,"position":1,"is_corresponding":false},{"id":57566,"name":"G. Marius Clore","orcid":"0000-0003-3809-1027","position":2,"is_corresponding":false},{"id":443259,"name":"Thomas Schmidt","orcid":"0000-0001-8116-7555","position":0,"is_corresponding":true}],"reference_count":38,"raw_metadata":null,"created_at":"2026-07-19T02:00:43.618468Z","pmid":"38888555","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":[]}