title: Bacterial expression of mouse argonaute 2 for functional and mutational studies.
abstract: RNA interference (RNAi) is a post-transcriptional gene-silencing process that occurs in many eukaryotic organisms upon intracellular exposure to double-stranded RNA. Argonaute 2 (Ago2) protein is the catalytic engine of mammalian RNAi. It contains a PIWI domain that is structurally related to RNases H and possibly shares with them a two-metal-ion catalysis mechanism. Here we describe the expression in E. coli of mouse Ago2 and testing of its enzymatic activity in a RISC assay, i.e., for the ability to cleave a target RNA in a single position specified by a complementary small interfering RNA (siRNA). The results show that the enzyme can load the siRNA and cleave the complementary RNA in absence of other cellular factors, as described for human Ago2. It was also found that mutation of Arg669, a residue previously proposed to be involved in substrate and/or B metal ion binding, doesn't affect the enzymatic activity, suggesting that this residue doesn't belong to the active site.
authors.affiliation: Department of Life Sciences, Second University of Naples, Caserta, Italy. salvatore.enzo@gmail.com
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Salvatore
authors.forename: Nicoletta
authors.initials: N
authors.lastname: Potenza
authors.forename: Umberto
authors.initials: U
authors.lastname: Papa
authors.forename: Valentina
authors.initials: V
authors.lastname: Nobile
authors.forename: Aniello
authors.initials: A
authors.lastname: Russo
mesh_terms: D000818:Animals; D060565:Argonaute Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D004926:Escherichia coli / Q000378:metabolism; D058619:Maltose-Binding Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D016297:Mutagenesis, Site-Directed; D034622:RNA Interference; D018075:RNA, Complementary / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification; D013379:Substrate Specificity
chemical_list: C526735:Ago2 protein, mouse; D060565:Argonaute Proteins; D058619:Maltose-Binding Proteins; D018075:RNA, Complementary; D034741:RNA, Small Interfering; D011993:Recombinant Fusion Proteins
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