title: The 9-A solution: how mRNA pseudoknots promote efficient programmed -1 ribosomal frameshifting.
abstract: There is something special about mRNA pseudoknots that allows them to elicit efficient levels of programmed -1 ribosomal frameshifting. Here, we present a synthesis of recent crystallographic, molecular, biochemical, and genetic studies to explain this property. Movement of 9 A by the anticodon loop of the aminoacyl-tRNA at the accommodation step normally pulls the downstream mRNA a similar distance along with it. We suggest that the downstream mRNA pseudoknot provides resistance to this movement by becoming wedged into the entrance of the ribosomal mRNA tunnel. These two opposing forces result in the creation of a local region of tension in the mRNA between the A-site codon and the mRNA pseudoknot. This can be relieved by one of two mechanisms; unwinding the pseudoknot, allowing the downstream region to move forward, or by slippage of the proximal region of the mRNA backwards by one base. The observed result of the latter mechanism is a net shift of reading frame by one base in the 5' direction, that is, a -1 ribosomal frameshift.
authors.affiliation: Department of Cell Biology and Molecular Genetics, Microbiology Building, University of Maryland, College Park, MD 20742, USA.
authors.forename: Ewan P
authors.initials: EP
authors.lastname: Plant
authors.forename: Kristi L Muldoon
authors.initials: KL
authors.lastname: Jacobs
authors.forename: Jason W
authors.initials: JW
authors.lastname: Harger
authors.forename: Arturas
authors.initials: A
authors.lastname: Meskauskas
authors.forename: Jonathan L
authors.initials: JL
authors.lastname: Jacobs
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Baxter
authors.forename: Alexey N
authors.initials: AN
authors.lastname: Petrov
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Dinman
mesh_terms: D001419:Bacteria / Q000737:chemistry / Q000378:metabolism; D018965:Frameshifting, Ribosomal / Q000502:physiology*; D012333:RNA, Messenger / Q000737:chemistry* / Q000378:metabolism*; D012270:Ribosomes / Q000378:metabolism*; D013816:Thermodynamics
chemical_list: D012333:RNA, Messenger