Video Experimental Relacionado

Updated: Nov 17, 2025

Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions

Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions

Published on: July 17, 2020

La reconstitución de un sistema PKS de tipo II de alta reducción revela que se requiere electrociclado 6π para la

Jie Zhang¹, Satoshi Yuzawa¹, Wei Li Thong¹

¹Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.

Journal of the American Chemical Society

|February 12, 2021

Resumen

Los investigadores aclararon la biosíntesis de productos naturales raros de o-dialquilbenceno. Reconstituyeron la biosíntesis del compuesto 1 in vitro, revelando una nueva vía que involucra una electrociclasa y una enzima similar a la tioesterasa.

Área de la Ciencia:

La bioquímica
Biosíntesis de productos naturales
Metabolismo secundario microbiano

Sus antecedentes:

Los productos naturales con fracciones de o-dialquilbenceno poseen diversas bioactividades.
Las vías de biosíntesis de los o-dialquilbenzenos son en gran medida desconocidas.
Las especies de Streptomyces son productores prolíficos de metabolitos secundarios bioactivos.

Objetivo del estudio:

Identificar el grupo de genes biosintéticos (BGC) para los compuestos 1 y 2 de Streptomyces sp. SANK 60404. ¿Qué es lo que quiere decir?
Para reconstituir la biosíntesis del compuesto 1 in vitro.
Elucidar la vía biosintética para el grupo o-tolil dentro de la fracción o-dialquilbenceno.

Principales métodos:

Identificación del grupo de genes biosintéticos (BGC) en Streptomyces sp. SANK 60404. ¿Qué es lo que quiere decir?
Reconstitución in vitro de la biosíntesis del compuesto 1 utilizando 22 enzimas recombinantes.
Caracterización enzimática de las enzimas clave, incluida una presunta isomerasa ("electrociclasa") y una enzima tipo tioesterasa.
Análisis bioinformático de genes conservados en BGCs relacionados.

Principales resultados:

Se identificó el BGC para los compuestos 1 y 2, con una parte rara de o-dialquilbenceno.
Se logró una reconstitución in vitro exitosa de la biosíntesis del compuesto 1.
Se estableció una nueva ruta de biosíntesis, que involucra una proteína portadora de acilo (ACP) única, un sistema de policetida sintasa (PKS) de tipo II, una electrociclasa y una enzima similar a la tioesterasa.
Se demostró que la electrociclasa isomeriza un intermediario para facilitar la electrociclado 6π intramolecular, seguido de la deshidrogenación.

Conclusiones:

El estudio estableció una ruta de biosíntesis para el grupo o-tolil dentro de los o-dialquilbenzenos.
El mecanismo propuesto que involucra una electrociclasa y una enzima similar a la tioesterasa proporciona nuevos conocimientos sobre la formación de esta fracción.
Los genes clave conservados sugieren que esta estrategia biosintética es común en la naturaleza para producir o-dialquilbenzenos.

Más Videos Relacionados

[DPEPhosbcpCu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst

[DPEPhosbcpCu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst

Published on: May 21, 2019

Electroactive Polymer Nanoparticles Exhibiting Photothermal Properties

Electroactive Polymer Nanoparticles Exhibiting Photothermal Properties

Published on: January 8, 2016

Videos de Conceptos Relacionados

Benzene to 1,4-Cyclohexadiene: Birch Reduction Mechanism

Benzene to 1,4-Cyclohexadiene: Birch Reduction Mechanism

Birch reduction uses solvated electrons as reducing agents. The reaction converts benzene to 1,4-cyclohexadiene. The reaction proceeds by the transfer of a single electron to the ring to form a benzene radical anion. This anion is highly basic—it abstracts a proton from the alcohol to form a cyclohexadienyl radical. Another single electron transfer gives the cyclohexadienyl anion. A proton transfer from the alcohol forms 1,4-cyclohexadiene. Since this reduction occurs via radical anion...

Thermal and Photochemical Electrocyclic Reactions: Overview

Thermal and Photochemical Electrocyclic Reactions: Overview

Electrocyclic reactions are reversible reactions. They involve an intramolecular cyclization or ring-opening of a conjugated polyene. Shown below are two examples of electrocyclic reactions. In the first reaction, the formation of the cyclic product is favored. In contrast, in the second reaction, ring-opening is favored due to the high ring strain associated with cyclobutene formation.

Vicinal Diols via Reductive Coupling of Aldehydes or Ketones: Pinacol Coupling Overview

Vicinal Diols via Reductive Coupling of Aldehydes or Ketones: Pinacol Coupling Overview

Wilhelm Rudolph Fittig discovered the pinacol coupling reaction in 1859. It is a radical dimerization reaction and involves the reductive coupling of aldehydes or ketones in the presence of hydrocarbon solvent to yield vicinal diols.

Photochemical Electrocyclic Reactions: Stereochemistry

Photochemical Electrocyclic Reactions: Stereochemistry

The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
Selection Rules: Photochemical Activation

Reactions at the Benzylic Position: Oxidation and Reduction

Reactions at the Benzylic Position: Oxidation and Reduction

The benzylic position describes the position of a carbon atom attached directly to a benzene ring. Benzene by itself does not undergo oxidation. In contrast, the benzylic carbon is quite reactive in the presence of strong oxidizing agents such as KMnO4 or H2CrO4. Therefore, alkylbenzenes are readily oxidized to benzoic acid, irrespective of the type of alkyl groups.

Reduction of Benzene to Cyclohexane: Catalytic Hydrogenation

Reduction of Benzene to Cyclohexane: Catalytic Hydrogenation

Unlike the easy catalytic hydrogenation of an alkene double bond, hydrogenation of a benzene double bond under similar reaction conditions does not take place easily. For example, in the reduction of stilbene, the benzene ring remains unaffected while the alkene bond gets reduced. Hydrogenation of an alkene double bond is exothermic and a favorable process. In contrast, to hydrogenate the first unsaturated bond of benzene, an energy input is needed; that is, the process is endothermic. This is...