Video Experimental Relacionado

Updated: Nov 24, 2025

Single Molecule Fluorescence Energy Transfer Study of Ribosome Protein Synthesis

Single Molecule Fluorescence Energy Transfer Study of Ribosome Protein Synthesis

Published on: July 6, 2021

Liberación de protones con compuertas durante la transferencia radical en la interfaz de subunidad de la

Chang Cui¹, Brandon L Greene², Gyunghoon Kang^3,4

¹Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States.

Journal of the American Chemical Society

|December 23, 2020

Resumen

La regulación de la transferencia de radicales en la ribonucleótida reductasa de Escherichia coli es crucial. El glutamato 52 (E52) controla la oxidación de la tirosina 356 (Y356) mediante la gestión de la liberación de protones, esencial para el transporte de radicales a través de la interfaz proteica.

Área de la Ciencia:

La bioquímica
Enzimología
Interacciones proteína-proteína

Sus antecedentes:

La ribonucleotida reductasa (RNR) de clase Ia en Escherichia coli facilita la síntesis de ADN a través de la transferencia de radicales.
La transferencia de radicales de largo alcance ocurre entre las subunidades α y β a través de aminoácidos redox-activos.
La regulación en la interfaz de la subunidad es fundamental para la función RNR.

Objetivo del estudio:

Investigar el papel del residuo E52 en la regulación de la oxidación de Y356 en la interfaz de las subunidades α-β.
Determinar el mecanismo de transferencia de protones en el control del transporte de radicales.
Elucidar el mecanismo de bloqueo para la transferencia de radicales a través de la interfaz proteína-proteína.

Principales métodos:

Mutagénesis dirigida al sitio (variante E52Q).
Estudios de oxidación fotoquímica con un fotooxidante unido covalentemente.
Espectroscopia de absorción y emisión transitoria.
Análisis de la oxidación y la rotación enzimática de Y356.

Principales resultados:

La variante E52Q es deficiente en la oxidación de Y356 a través de vías nativas y fotoquímicas.
El E52 es esencial para la liberación de protones, formando parte de un canal de agua en la interfaz.
La sustitución de Y356 por análogos en el mutante E52Q restauró la rotación fotoquímica.
Los datos espectroscópicos confirman el requisito de E52 para la oxidación y el manejo de protones de Y356.

Conclusiones:

El glutamato 52 (E52) es esencial para el transporte de radicales a través de la interfaz proteína-proteína en la RNR de clase Ia.
E52 regula la oxidación de Y356 mediante la gestión de la liberación de protones a través de un canal de agua.
Este manejo de protones es crítico para el mecanismo de transferencia de radicales de largo alcance.

Más Videos Relacionados

Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy

Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy

Published on: June 27, 2014

Studying Ribonucleotide Incorporation: Strand-specific Detection of Ribonucleotides in the Yeast Genome and Measuring Ribonucleotide-induced Mutagenesis

Studying Ribonucleotide Incorporation: Strand-specific Detection of Ribonucleotides in the Yeast Genome and Measuring Ribonucleotide-induced Mutagenesis

Published on: July 26, 2018

Videos de Conceptos Relacionados

Radical Reactivity: Overview

Radical Reactivity: Overview

Radicals, the highly reactive species, gain stability by undergoing three different reactions. The first reaction involves a radical-radical coupling, in which a radical combines with another radical, forming a spin‐paired molecule. The second reaction is between a radical and a spin‐paired molecule, generating a new radical and a new spin‐paired molecule. The third reaction is radical decomposition in a unimolecular reaction, forming a new radical and a spin‐paired...

Radical Reactivity: Nucleophilic Radicals

Radical Reactivity: Nucleophilic Radicals

Radicals adjacent to electron-donating groups are called nucleophilic radicals. These radicals readily react with electrophilic alkenes. The SOMO–LUMO interactions are the driving force for the reaction, where the high-energy SOMO of the electron-rich, nucleophilic radicals interacts with the low-energy LUMO of the electron-deficient, electrophilic alkenes. Such SOMO–LUMO interactions are the basis of reactive radical traps, affecting the selectivity in radical reactions. For...

Rab Proteins

Rab Proteins

Rab proteins constitute the largest family of monomeric GTPases, of which 70 members are present in humans. Rab proteins and their effectors regulate consecutive stages of vesicle transport such as vesicle transport, docking, and fusion to the correct recipient membrane.
Rab proteins switch between a cytosolic, GDP-bound inactive state and a membrane-anchored, GTP-bound active state. By themselves, Rabs show slow rates of GDP/GTP exchange and GTP hydrolysis. Thus, Rab proteins are considered...

Radical Reactivity: Intramolecular vs Intermolecular

Radical Reactivity: Intramolecular vs Intermolecular

Radical reactions can occur either intermolecularly or intramolecularly. In an intermolecular radical reaction, a nucleophilic radical adds to an electrophilic alkene or vice versa. In such reactions, the radical and generally the alkene, which is also called the radical trap, are two different molecules. Additionally, for such intermolecular reactions to occur, the radical trap must be active, present in an excess concentration, and the radical starting material must have a weak...

Small GTPases - Ras and Rho

Small GTPases - Ras and Rho

Ras and Rho are small monomeric GTPases that act downstream of receptor tyrosine kinase (RTK) and regulate various cellular processes. These GTPases switch between active and inactive states by binding to guanine nucleotides.
Three regulatory proteins control their activity:

ATP Synthase: Mechanism

ATP Synthase: Mechanism

In animals, the mitochondrial F1F0 ATP synthase is the key protein that synthesizes ATP molecules through a complex catalytic mechanism. While the nuclear genome encodes the majority of ATP synthase subunits, the mitochondrial genome encodes some of the enzyme's most critical components. The formation of this multi-subunit enzyme is a complex multi-step process regulated at the level of transcription, translation, and assembly. Defects in one or more of these steps can result in decreased...