Video Experimental Relacionado
Updated: Jun 20, 2026
07:55
Luciferase Complementation Imaging Assay in Nicotiana benthamiana Leaves for Transiently Determining Protein-protein Interaction Dynamics
Published on: November 20, 2017
La transferencia de protones inducida por la luz en microsegundos a la flavina en la planta de sensores de luz azul
Thomas Langenbacher1, Dominik Immeln, Bernhard Dick
1Institut für Physikalische und Theoretische Chemie, Universität Regensburg, 93053 Regensburg, Germany.
Journal of the American Chemical Society
|September 17, 2009
Resumen
Las criptocromas de las plantas, los sensores de luz azul, se someten a fotorreducción rápida. Se identificó un nuevo paso de transferencia de protones de microsegundos, distinto de los criptocromos y las fotoliasas animales.
Área de la Ciencia:
- Biología vegetal Biología vegetal
- Investigación de los fotorreceptores.
- La bioquímica es la bioquímica.
Sus antecedentes:
- Los criptocromos de las plantas son fotorreceptores de luz azul cruciales para el crecimiento de las plantas, los ritmos diarios y potencialmente la magnetorrecepción.
- Comparten similitudes estructurales con las fotoliasas de reparación del ADN y utilizan el dinucleótido de adenina flavina (FAD) como cromóforo.
- La absorción de luz desencadena la fotorreducción de la flavina, generando un radical neutro de señalización de la flavina.
Objetivo del estudio:
- Para investigar la dinámica ultrarrápida de la fotorreducción criptocromo más allá de la escala de tiempo de milisegundos.
- Para dilucidar la secuencia temporal de los eventos de transferencia de electrones y protones en criptocromos de algas.
- Para comparar el mecanismo de fotorreducción con los criptocromos y las fotoliasas animales.
Principales métodos:
- Espectroscopia de absorción con resolución de tiempo utilizando una configuración de cámara de rayas.
- Monitoreo de cambios espectrales en el rango de 375-750 nm.
- Análisis de cambios de absorción inducidos por la luz para determinar la cinética de la reacción.
Principales resultados:
- La transferencia de electrones del triptófano a la flavina ocurre dentro de los 100 ns, formando un radical aniónico de flavina.
- Un paso de transferencia de protones con una constante de tiempo de 1,7 microsegundos genera el radical neutro flavin.
- La desintegración del radical flavin y el radical triptófano ocurre en >200 microsegundos, milisegundos y segundos.
Conclusiones:
- La transferencia de protones de microsegundos observada es única en los criptocromos de plantas/algas y no se observa en sus contrapartes animales o en las fotoliasas.
- La clara separación temporal de la transferencia de electrones y protones es un hallazgo novedoso en la investigación de los fotorreceptores flavinos.
- La cinética de la reacción sugiere que el donante de protones no está a una distancia cercana de enlace de hidrógeno con la flavina N5, lo que lleva a una mayor investigación sobre posibles donantes y el papel de la tríada de triptófano.
Más Videos Relacionados
09:32Light-mediated Reversible Modulation of the Mitogen-activated Protein Kinase Pathway during Cell Differentiation and Xenopus Embryonic Development
Published on: June 15, 2017
11:10Protein-protein Interactions Visualized by Bimolecular Fluorescence Complementation in Tobacco Protoplasts and Leaves
Published on: March 9, 2014
Videos de Conceptos Relacionados
02:00Photoreceptors and Plant Responses to Light
Light plays a significant role in regulating the growth and development of plants. In addition to providing energy for photosynthesis, light provides other important cues to regulate a range of developmental and physiological responses in plants.
01:11Channel Rhodopsins
Most organisms use photoreceptors to sense and respond to light. Examples of photoreceptors include bacteriorhodopsins and bacteriophytochromes in some bacteria, phytochromes in plants, and rhodopsins in the photoreceptor cells of the vertebral retina. The light-sensitive property of these receptors is because of the bound chromophores, such as bilin in the phytochromes and retinal in the rhodopsins.
Rhodopsins belong to the family of cell surface proteins called G-protein coupled receptors,...
Rhodopsins belong to the family of cell surface proteins called G-protein coupled receptors,...
02:45Biological Clocks and Seasonal Responses
The circadian—or biological—clock is an intrinsic, timekeeping, molecular mechanism that allows plants to coordinate physiological activities over 24-hour cycles called circadian rhythms. Photoperiodism is a collective term for the biological responses of plants to variations in the relative lengths of dark and light periods. The period of light-exposure is called the photoperiod.
01:19Protein Dynamics in Living Cells
Different fluorescence-based techniques are used to study the protein dynamics in living cells. These techniques include FRAP, FRET, and PET.
Fluorescent recovery after photobleaching (FRAP) is a fluorescent-protein-based detection technique used to quantify protein movement rates within the cell. This method exposes a small portion of the cell to an intense laser beam. The laser beam causes permanent photobleaching of the fluorophore-tagged proteins in the exposed region. As the bleached...
Fluorescent recovery after photobleaching (FRAP) is a fluorescent-protein-based detection technique used to quantify protein movement rates within the cell. This method exposes a small portion of the cell to an intense laser beam. The laser beam causes permanent photobleaching of the fluorophore-tagged proteins in the exposed region. As the bleached...
01:22Photosystem II
The multi-protein complex photosystem II (PS II) harvests photons and transfers their energy through its bound pigments to its reaction center, and ultimately to photosystem I (PSI) through the electron transport chain. The pigments responsible for caputirng the light energy in photosystems include chlorophyll a, chlorophyll b, and carotenoids.
The pigment molecules are arranged across two photosystem domains — the antenna complex and the reaction center. The main aim of the pigment molecules...
The pigment molecules are arranged across two photosystem domains — the antenna complex and the reaction center. The main aim of the pigment molecules...
01:22Photoreceptors and Visual Pathways
At the molecular level, visual signals trigger transformations in photopigment molecules, resulting in changes in the photoreceptor cell's membrane potential. The photon's energy level is denoted by its wavelength, with each specific wavelength of visible light associated with a distinct color. The spectral range of visible light, classified as electromagnetic radiation, spans from 380 to 720 nm. Electromagnetic radiation wavelengths exceeding 720 nm fall under the infrared category, whereas...