{"doi":"10.1101/2021.06.29.450373","title":"Mapping of the fibrinogen-binding site on the staphylocoagulase C-terminal repeat region","abstract":"Abstract The N-terminus of S. aureus staphylocoagulase (SC) triggers activation of host prothrombin (ProT), and the SC·ProT* complex cleaves host fibrinogen (Fbg) to form fibrin (Fbn) deposits, a hallmark of SC-positive endocarditis. The C-terminal domain of the prototypical Newman D2 Tager 104 SC contains 1 pseudo-repeat (PR) and 7 repeats (R1→R7) that bind Fbg/Fbn Fragment D (Frag D). This work defines affinities and stoichiometries of Frag D binding to single- and multi-repeat C-terminal constructs, using fluorescence equilibrium binding, NMR titration, Ala scanning, and native PAGE. Constructs containing PR and each single repeat bound Frag D with K D ~50 - 130 nM and a 1:1 stoichiometry, indicating a conserved binding site shared between PR and each repeat. NMR titration of PR-R7 with Frag D revealed that residues 22-49, bridging PR and R7, constituted the minimal peptide (MP) required for binding, corroborated by Ala scanning, and binding of labeled MP to Frag D. MP alignment with the PR-repeat and inter-repeat junctions identified conserved residues critical for binding. Labeled PR-(R1→R7) bound Frag D with K D ~7 - 32 nM and stoichiometry of 1:5; and PR-R1R2R3, PR-R1R6R7, PR-R3R4R7, and PR-R3R6R7 competed with PR-(R1→R7) for Frag D binding, with a 1:3 stoichiometry and K D ~7 - 42 nM. These findings are consistent with binding at the PR-R junctions with modest inter-repeat sequence variability. Circular dichroism of PR-R7 and PR-(R1→R7) suggested a largely disordered structure and conformational flexibility, allowing binding of multiple fibrin(ogen) molecules. This property facilitates pathogen localization on host fibrin networks.","journal":"bioRxiv (Cold Spring Harbor Laboratory)","year":2021,"id":221136,"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":1,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9655,"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":404558,"name":"Markus Voehler","orcid":"0000-0002-9509-6396","position":1,"is_corresponding":false},{"id":517812,"name":"Peter Panizzi","orcid":"0000-0003-0141-8807","position":2,"is_corresponding":false},{"id":36757,"name":"Jens Meiler","orcid":"0000-0001-8945-193X","position":3,"is_corresponding":false},{"id":518610,"name":"Paul Bock","orcid":null,"position":4,"is_corresponding":false},{"id":517813,"name":"Ingrid M. Verhamme","orcid":"0000-0003-1301-4308","position":5,"is_corresponding":false},{"id":518607,"name":"Ashoka A. Maddur","orcid":null,"position":0,"is_corresponding":true}],"reference_count":66,"raw_metadata":null,"created_at":"2026-07-18T23:53:50.838581Z","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":[]}