title: Autonomously folded α-helical lockers promote RNAi.
abstract: RNAi is an indispensable research tool with a substantial therapeutic potential. However, the complete transition of the approach to an applied capability remains hampered due to poorly understood relationships between siRNA delivery and gene suppression. Here we propose that interfacial tertiary contacts between α-helices can regulate siRNA cytoplasmic delivery and RNAi. We introduce a rationale of helical amphipathic lockers that differentiates autonomously folded helices, which promote gene silencing, from helices folded with siRNA, which do not. Each of the helical designs can deliver siRNA into cells via energy-dependent endocytosis, while only autonomously folded helices with pre-locked hydrophobic interfaces were able to promote statistically appreciable gene silencing. We propose that it is the amphipathic locking of interfacing helices prior to binding to siRNA that enables RNAi. The rationale offers structurally balanced amphipathic scaffolds to advance the exploitation of functional RNAi.
authors.affiliation: Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, CB2 3RA, UK.|National Physical Laboratory, Teddington, Middlesex, TW11 0WL, UK.
authors.forename: Christian P E
authors.initials: CP
authors.lastname: Guyader
authors.affiliation: National Physical Laboratory, Teddington, Middlesex, TW11 0WL, UK.
authors.forename: Baptiste
authors.initials: B
authors.lastname: Lamarre
authors.affiliation: National Physical Laboratory, Teddington, Middlesex, TW11 0WL, UK.
authors.forename: Emiliana
authors.initials: E
authors.lastname: De Santis
authors.affiliation: National Physical Laboratory, Teddington, Middlesex, TW11 0WL, UK.
authors.forename: James E
authors.initials: JE
authors.lastname: Noble
authors.affiliation: Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, CB2 3RA, UK.
authors.forename: Nigel K
authors.initials: NK
authors.lastname: Slater
authors.affiliation: National Physical Laboratory, Teddington, Middlesex, TW11 0WL, UK.
authors.forename: Maxim G
authors.initials: MG
authors.lastname: Ryadnov
mesh_terms: D002470:Cell Survival; D003593:Cytoplasm / Q000235:genetics; D020868:Gene Silencing; D057809:HEK293 Cells; D006801:Humans; D010455:Peptides / Q000737:chemistry* / Q000235:genetics; D000072756:Protein Conformation, alpha-Helical; D017510:Protein Folding; D034741:RNA, Small Interfering / Q000494:pharmacology*
chemical_list: D010455:Peptides; D034741:RNA, Small Interfering