title: Structure and function of RapA: a bacterial Swi2/Snf2 protein required for RNA polymerase recycling in transcription.
abstract: One of the hallmarks of the Swi2/Snf2 family members is their ability to modify the interaction between DNA-binding protein and DNA in controlling gene expression. The studies of Swi2/Snf2 have been mostly focused on their roles in chromatin and/or nucleosome remodeling in eukaryotes. A bacterial Swi2/Snf2 protein named RapA from Escherichia coli is a unique addition to these studies. RapA is an RNA polymerase (RNAP)-associated protein and an ATPase. It binds nucleic acids including RNA and DNA. The ATPase activity of RapA is stimulated by its interaction with RNAP, but not with nucleic acids. RapA and the major sigma factor σ70 compete for binding to core RNAP. After one transcription cycle in vitro, RNAP is immobilized in an undefined posttranscription/posttermination complex (PTC), thus becoming unavailable for reuse. RapA stimulates RNAP recycling by ATPase-dependent remodeling of PTC, leading to the release of sequestered RNAP, which then becomes available for reuse in another cycle of transcription. Recently, the crystal structure of RapA that is also the first full-length structure for the entire Swi2/Snf2 family was determined. The structure provides a framework for future studies of the mechanism of RNAP recycling in transcription. This article is part of a Special Issue entitled: Snf2/Swi2 ATPase structure and function.
authors.affiliation: Center for Cancer Research, Natioal Cancer Institute, National Institute of Health, Frederick, MD 21702, USA. djjin@helix.nih.gov
authors.forename: Ding Jun
authors.initials: DJ
authors.lastname: Jin
authors.forename: Yan Ning
authors.initials: YN
authors.lastname: Zhou
authors.forename: Gary
authors.initials: G
authors.lastname: Shaw
authors.forename: Xinhua
authors.initials: X
authors.lastname: Ji
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry* / Q000378:metabolism*; D004269:DNA, Bacterial / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012321:DNA-Directed RNA Polymerases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D008958:Models, Molecular; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D012808:Sigma Factor / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D015533:Transcriptional Activation
chemical_list: D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D012808:Sigma Factor; D014157:Transcription Factors; C412226:RapA ATPase; D012321:DNA-Directed RNA Polymerases; D000251:Adenosine Triphosphatases