Video Experimental Relacionado
Updated: Jun 26, 2026
10:50
Directed Evolution Method in Saccharomyces cerevisiae: Mutant Library Creation and Screening
Published on: April 1, 2016
La evolución in vitro sugiere múltiples orígenes para la ribozima cabeza de martillo
K Salehi-Ashtiani1, J W Szostak
1Howard Hughes Medical Institute and Department of Molecular Biology, Massachusetts General Hospital, Boston 02114, USA.
Nature
|November 2, 2001
Resumen
La ribozima de cabeza de martillo, un motivo de ARN autoclasificado, es la estructura más simple y más común para la autoclasificación del ARN en condiciones fisiológicas. Esto sugiere que la evolución favorece la solución más simple para los problemas bioquímicos, explicando su ocurrencia generalizada.
Área de la Ciencia:
- Biología Molecular Biología Molecular
- Biología evolutiva Biología evolutiva.
- La bioquímica es la bioquímica.
Sus antecedentes:
- La ribozima de la cabeza de martillo es un motivo de ARN autoclavado que se encuentra en diversos organismos, incluidas las plantas, los tritones, los esquistosomas y los grillos de cueva.
- Su distribución esporádica sugiere orígenes antiguos o evolución independiente en diferentes especies.
- Comprender las presiones evolutivas que dan forma a la distribución de la ribozima es crucial.
Objetivo del estudio:
- Para investigar los orígenes evolutivos y la distribución de la ribozima cabeza de martillo.
- Determinar la estructura de ARN más simple capaz de auto-clivado a tasas biológicamente relevantes.
- Explorar si los procesos evolutivos favorecen soluciones más simples para las funciones bioquímicas.
Principales métodos:
- Se empleó la selección in vitro para examinar una biblioteca imparcial de secuencias aleatorias de ARN.
- La selección tuvo como objetivo identificar motivos de autoclave con una actividad comparable a las conocidas ribozimas de cabeza de martillo.
- Los experimentos se llevaron a cabo en condiciones casi fisiológicas para imitar entornos biológicos.
Principales resultados:
- El motivo de la ribozima cabeza de martillo surgió como la estructura de ARN más común y más simple capaz de auto-clivado.
- Esta auto-escisión se produjo a tasas comparables a las observadas en los sistemas biológicos.
- Los hallazgos fueron consistentes a través de condiciones casi fisiológicas.
Conclusiones:
- La prevalencia de la ribozima cabeza de martillo sugiere que las vías evolutivas a menudo se canalizan hacia las soluciones bioquímicas más simples.
- Este principio de selección de la estructura funcional más simple puede explicar su presencia generalizada en la naturaleza.
- La selección de laboratorio refleja los procesos evolutivos naturales en favor de la simplicidad.
Videos de Conceptos Relacionados
00:43Bacterial RNA Polymerase
Unlike eukaryotes, bacteria use a single RNA Polymerase (RNAP) to transcribe all genes. The different subunits of bacterial RNAPhave distinct functions. The multisubunit structure of the bacterial RNAP helps the enzyme to maintain catalytic function, facilitate assembly, interact with DNA and RNA, and self-regulate its activity.
In most genes, the transcription site is a single base present upstream of the coding sequence. Though RNAP is a catalytically efficient enzyme, it does not recognize...
In most genes, the transcription site is a single base present upstream of the coding sequence. Though RNAP is a catalytically efficient enzyme, it does not recognize...
02:47Ribozymes
The term ribozyme is used for RNA that can act as an enzyme. Ribozymes are mainly found in selected viruses, bacteria, plant organelles, and lower eukaryotes. Ribozymes were first discovered in 1982 when Tom Cech’s laboratory observed Group I introns acting as enzymes. This was shortly followed by the discovery of another ribozyme, Ribonulcease P, by Sid Altman’s laboratory. Both Cech and Altman received the Nobel Prize in chemistry in 1989 for their work on ribozymes.
Ribozymes can be...
Ribozymes can be...
02:32Exon Recombination
The evolution of new genes is critical for speciation. Exon recombination, also known as exon shuffling or domain shuffling, is an important means of new gene formation. It is observed across vertebrates, invertebrates, and in some plants such as potatoes and sunflowers. During exon recombination, exons from the same or different genes recombine and produce new exon-intron combinations, which might evolve into new genes.
Exon shuffling follows “splice frame rules.” Each exon has three reading...
Exon shuffling follows “splice frame rules.” Each exon has three reading...
02:47Ribozymes
The term ribozyme is used for RNA that can act as an enzyme. Ribozymes are mainly found in selected viruses, bacteria, plant organelles, and lower eukaryotes. Ribozymes were first discovered in 1982 when Tom Cech’s laboratory observed Group I introns acting as enzymes. This was shortly followed by the discovery of another ribozyme, Ribonulcease P, by Sid Altman’s laboratory. Both Cech and Altman received the Nobel Prize in chemistry in 1989 for their work on ribozymes.
Ribozymes can be...
Ribozymes can be...
01:24Eukaryotic Evolution
The endosymbiont theory is the most widely accepted theory of eukaryotic evolution; however, its progression is still somewhat debated. According to the nucleus-first hypothesis, the ancestral prokaryote first evolved a membrane to enclose DNA and form the nucleus. Conversely, the mitochondria-first hypothesis suggests that the nucleus was formed after endosymbiosis of mitochondria.
Contrary to the endosymbiont theory, the eukaryote-first hypothesis proposes that the simpler prokaryotic and...
Contrary to the endosymbiont theory, the eukaryote-first hypothesis proposes that the simpler prokaryotic and...
00:43Bacterial RNA Polymerase
Unlike eukaryotes, bacteria use a single RNA Polymerase (RNAP) to transcribe all genes. The different subunits of bacterial RNAPhave distinct functions. The multisubunit structure of the bacterial RNAP helps the enzyme to maintain catalytic function, facilitate assembly, interact with DNA and RNA, and self-regulate its activity.
In most genes, the transcription site is a single base present upstream of the coding sequence. Though RNAP is a catalytically efficient enzyme, it does not recognize...
In most genes, the transcription site is a single base present upstream of the coding sequence. Though RNAP is a catalytically efficient enzyme, it does not recognize...