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During sporulation SirA prevents DnaA association with the replication origin to prevent excessive chromosome replication (PubMed:19682252, PubMed:21239581). Alternatively SirA binds to domain I of DnaA and prevent its interaction with DnaD, preventing DNA replication initiation (PubMed:36416272). Upon ectopic expression during vegetative growth reduces chromosome copy number, leading to elongated cells with that can have a single nucleoid or be anucleate (PubMed:19329632, PubMed:19682252, PubMed:25041308). Ectopic expression during vegetative growth blocks DnaA at oriC while blocking recruitment of DnaD to oriC (PubMed:36416272). Plays a significant role during the onset of sporulation (PubMed:19682252)"}],"commentType":"FUNCTION"},{"texts":[{"evidences":[{"evidenceCode":"ECO:0000269","source":"PubMed","id":"19682252"},{"evidenceCode":"ECO:0000269","source":"PubMed","id":"21239581"},{"evidenceCode":"ECO:0000269","source":"PubMed","id":"25041308"},{"evidenceCode":"ECO:0000269","source":"PubMed","id":"36416272"}],"value":"Interacts with DnaA (PubMed:19682252, PubMed:36416272). Forms a 1:1 complex with domain I of DnaA (PubMed:21239581, PubMed:25041308)"}],"commentType":"SUBUNIT"},{"commentType":"SUBCELLULAR LOCATION","note":{"texts":[{"evidences":[{"evidenceCode":"ECO:0000269","source":"PubMed","id":"25041308"}],"value":"Localized at mid-cell in sporulating cells, not at the origin of replication, colocalizes with the replisome (the beta-sliding clamp subunit, DnaN)"}]},"subcellularLocations":[{"location":{"evidences":[{"evidenceCode":"ECO:0000269","source":"PubMed","id":"25041308"}],"value":"Cytoplasm","id":"SL-0086"}}]},{"texts":[{"evidences":[{"evidenceCode":"ECO:0000269","source":"PubMed","id":"19329632"},{"evidenceCode":"ECO:0000269","source":"PubMed","id":"25041308"}],"value":"Up-regulated by spo0A (PubMed:19329632). Expressed during sporulation, commencing between 90 and 120 minutes after sporulation induction in about 20% of the cells (at protein level) (PubMed:25041308)"}],"commentType":"INDUCTION"},{"texts":[{"evidences":[{"evidenceCode":"ECO:0000269","source":"PubMed","id":"19329632"},{"evidenceCode":"ECO:0000269","source":"PubMed","id":"19682252"},{"evidenceCode":"ECO:0000269","source":"PubMed","id":"36416272"}],"value":"Increases the number of observed replication origins (PubMed:19329632, PubMed:19682252). 15% reduction in sporulation efficiency, chromosomes continue to replicate during sporulation (PubMed:19682252). Both DnaA and DnaD rest longer than normal at oriC during sporulation onset, more sporulating cells have active replisomes (PubMed:36416272)"}],"commentType":"DISRUPTION PHENOTYPE"},{"texts":[{"evidences":[{"evidenceCode":"ECO:0000305"}],"value":"Belongs to the SirA family"}],"commentType":"SIMILARITY"}],"features":[{"type":"Chain","location":{"start":{"value":1,"modifier":"EXACT"},"end":{"value":148,"modifier":"EXACT"}},"description":"Sporulation inhibitor of replication protein SirA","featureId":"PRO_0000049647"},{"type":"Mutagenesis","location":{"start":{"value":18,"modifier":"EXACT"},"end":{"value":18,"modifier":"EXACT"}},"description":"No longer localizes to mid-cell during sporulation, not toxic in growing cells, 2.5-fold reduced interaction with domain I of DnaA in E.coli.","evidences":[{"evidenceCode":"ECO:0000269","source":"PubMed","id":"25041308"}],"alternativeSequence":{"originalSequence":"Y","alternativeSequences":["A"]}},{"type":"Beta strand","location":{"start":{"value":3,"modifier":"EXACT"},"end":{"value":10,"modifier":"EXACT"}},"description":"","evidences":[{"evidenceCode":"ECO:0007829","source":"PDB","id":"4TPS"}]},{"type":"Helix","location":{"start":{"value":12,"modifier":"EXACT"},"end":{"value":17,"modifier":"EXACT"}},"description":"","evidences":[{"evidenceCode":"ECO:0007829","source":"PDB","id":"4TPS"}]},{"type":"Turn","location":{"start":{"value":18,"modifier":"EXACT"},"end":{"value":20,"modifier":"EXACT"}},"description":"","evidences":[{"evidenceCode":"ECO:0007829","source":"PDB","id":"4TPS"}]},{"type":"Helix","location":{"start":{"value":22,"modifier":"EXACT"},"end":{"value":33,"modifier":"EXACT"}},"description":"","evidences":[{"evidenceCode":"ECO:0007829","source":"PDB","id":"4TPS"}]},{"type":"Helix","location":{"start":{"value":39,"modifier":"EXACT"},"end":{"value":52,"modifier":"EXACT"}},"description":"","evidences":[{"evidenceCode":"ECO:0007829","source":"PDB","id":"4TPS"}]},{"type":"Helix","location":{"start":{"value":58,"modifier":"EXACT"},"end":{"value":69,"modifier":"EXACT"}},"description":"","evidences":[{"evidenceCode":"ECO:0007829","source":"PDB","id":"4TPS"}]},{"type":"Beta strand","location":{"start":{"value":72,"modifier":"EXACT"},"end":{"value":77,"modifier":"EXACT"}},"description":"","evidences":[{"evidenceCode":"ECO:0007829","source":"PDB","id":"4TPS"}]},{"type":"Beta strand","location":{"start":{"value":80,"modifier":"EXACT"},"end":{"value":84,"modifier":"EXACT"}},"description":"","evidences":[{"evidenceCode":"ECO:0007829","source":"PDB","id":"4TPS"}]},{"type":"Helix","location":{"start":{"value":86,"modifier":"EXACT"},"end":{"value":88,"modifier":"EXACT"}},"description":"","evidences":[{"evidenceCode":"ECO:0007829","source":"PDB","id":"4TPS"}]},{"type":"Beta strand","location":{"start":{"value":90,"modifier":"EXACT"},"end":{"value":97,"modifier":"EXACT"}},"description":"","evidences":[{"evidenceCode":"ECO:0007829","source":"PDB","id":"4TPS"}]},{"type":"Beta strand","location":{"start":{"value":100,"modifier":"EXACT"},"end":{"value":108,"modifier":"EXACT"}},"description":"","evidences":[{"evidenceCode":"ECO:0007829","source":"PDB","id":"4TPS"}]},{"type":"Helix","location":{"start":{"value":110,"modifier":"EXACT"},"end":{"value":122,"modifier":"EXACT"}},"description":"","evidences":[{"evidenceCode":"ECO:0007829","source":"PDB","id":"4TPS"}]},{"type":"Beta strand","location":{"start":{"value":126,"modifier":"EXACT"},"end":{"value":130,"modifier":"EXACT"}},"description":"","evidences":[{"evidenceCode":"ECO:0007829","source":"PDB","id":"4TPS"}]},{"type":"Turn","location":{"start":{"value":131,"modifier":"EXACT"},"end":{"value":134,"modifier":"EXACT"}},"description":"","evidences":[{"evidenceCode":"ECO:0007829","source":"PDB","id":"4TPS"}]},{"type":"Beta strand","location":{"start":{"value":135,"modifier":"EXACT"},"end":{"value":138,"modifier":"EXACT"}},"description":"","evidences":[{"evidenceCode":"ECO:0007829","source":"PDB","id":"4TPS"}]}],"keywords":[{"id":"KW-0002","category":"Technical term","name":"3D-structure"},{"id":"KW-0963","category":"Cellular component","name":"Cytoplasm"},{"id":"KW-0236","category":"Molecular function","name":"DNA replication inhibitor"},{"id":"KW-1185","category":"Technical term","name":"Reference proteome"},{"id":"KW-0749","category":"Biological process","name":"Sporulation"}],"references":[{"referenceNumber":1,"citation":{"id":"9068642","citationType":"journal article","authors":["Schioett T.","von Wachenfeldt C.","Hederstedt L."],"citationCrossReferences":[{"database":"PubMed","id":"9068642"},{"database":"DOI","id":"10.1128/jb.179.6.1962-1973.1997"}],"title":"Identification and characterization of the ccdA gene, required for cytochrome c synthesis in Bacillus subtilis.","publicationDate":"1997","journal":"J. 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