A homodimer interface without base pairs in an RNA mimic of red fluorescent protein.
Nat Chem Biol
; 13(11): 1195-1201, 2017 Nov.
Article
em En
| MEDLINE
| ID: mdl-28945234
ABSTRACT
Corn, a 28-nucleotide RNA, increases yellow fluorescence of its cognate ligand 3,5-difluoro-4-hydroxybenzylidene-imidazolinone-2-oxime (DFHO) by >400-fold. Corn was selected in vitro to overcome limitations of other fluorogenic RNAs, particularly rapid photobleaching. We now report the Corn-DFHO co-crystal structure, discovering that the functional species is a quasisymmetric homodimer. Unusually, the dimer interface, in which six unpaired adenosines break overall two-fold symmetry, lacks any intermolecular base pairs. The homodimer encapsulates one DFHO at its interprotomer interface, sandwiching it with a G-quadruplex from each protomer. Corn and the green-fluorescent Spinach RNA are structurally unrelated. Their convergent use of G-quadruplexes underscores the usefulness of this motif for RNA-induced small-molecule fluorescence. The asymmetric dimer interface of Corn could provide a basis for the development of mutants that only fluoresce as heterodimers. Such variants would be analogous to Split GFP, and may be useful for analyzing RNA co-expression or association, or for designing self-assembling RNA nanostructures.
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Base de dados:
MEDLINE
Assunto principal:
Dimerização
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Aptâmeros de Nucleotídeos
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Quadruplex G
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Imagem Óptica
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Corantes Fluorescentes
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Proteínas Luminescentes
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Conformação de Ácido Nucleico
Idioma:
En
Ano de publicação:
2017
Tipo de documento:
Article
País de afiliação:
Estados Unidos