Video Experimental Relacionado
Updated: Jul 24, 2026
09:42
Unraveling Entropic Rate Acceleration Induced by Solvent Dynamics in Membrane Enzymes
Published on: January 16, 2016
Formación enzimática de un poliprenoide hexacíclico C35 no natural por la bacteriana squalene cyclase
Ikuro Abe1, Hideya Tanaka, Hiroshi Noguchi
1University of Shizuoka, School of Pharmaceutical Sciences, 52-1 Yada, Shizuoka 422-8526, Japan. abei@ys7.u-shizuoka-ken.ac.jp
Journal of the American Chemical Society
|December 6, 2002
Resumen
Las enzimas convirtieron un polipreno C35 no natural en una nueva estructura hexacíclica. Esto demuestra las enzimas ciclizadoras del escualeno.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Química orgánica es la química orgánica.
- Enzimología Enzimología.
Sus antecedentes:
- Las ciclasas de escualeno son enzimas cruciales en la biosíntesis de productos naturales.
- Comprender el alcance de su sustrato y sus mecanismos catalíticos es clave para descubrir nuevos compuestos.
Objetivo del estudio:
- Para investigar la conversión enzimática de un polipreno C35 no natural por el squalene:hopene cyclase.
- Para explorar la capacidad de la enzima para construir nuevos esqueletos hexacíclicos.
Principales métodos:
- Conversión enzimática mediante escualeno:hopeno ciclasa de Alicyclobacillus acidocaldarius.
- Caracterización del producto de ciclización.
Principales resultados:
- El polipreno C35 se convirtió con éxito en un poliprenoide hexacíclico no natural.
- Esto representa la primera demostración de una enzima que construye un esqueleto hexacíclico no natural.
- La ciclización se inició a través del ataque de protones en el enlace doble terminal de la unidad C15 sin reordenamiento.
Conclusiones:
- Las enzimas ciclizadoras de escualeno poseen una notable versatilidad para crear estructuras cíclicas complejas y antinaturales.
- Las conformaciones específicas del sustrato (silla-silla-silla-silla-barco-barco) son críticas para lograr la estereoquímica deseada en los productos de ciclización.
![Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F60786.jpg&w=3840&q=50)
Videos de Conceptos Relacionados
01:13Intramolecular Claisen Condensation of Dicarboxylic Esters: Dieckmann Cyclization
Dieckmann cyclization is an intramolecular Claisen condensation of diesters. The reaction occurs in the presence of a base and generates a cyclic β-ketoester as the final product. Commonly, 1, 6 and 1, 7-diesters are preferred substrates for the reaction since the generated five, and six-membered cyclic β-keto esters are particularly more stable.
01:28Diels–Alder Reaction Forming Cyclic Products: Stereochemistry
The Diels–Alder reaction is one of the robust methods for synthesizing unsaturated six-membered rings. The reaction involves a concerted cyclic movement of six π electrons: four π electrons from the diene and two π electrons from the dienophile.
01:01Ketones with Nonenolizable Aromatic Aldehydes: Claisen–Schmidt Condensation
Benzaldehyde, like formaldehyde, lacks an α hydrogen and cannot enolize to form an enolate. Hence, the reaction of benzaldehyde with a ketone in the presence of an aqueous base forms a single crossed product. This reaction is referred to as Claisen–Schmidt condensation.
As the self-condensation of ketones is generally not favored in basic conditions, the self-condensed products do not form in the reaction between ketones and benzaldehyde. The general reaction of Claisen–Schmidt condensation is...
As the self-condensation of ketones is generally not favored in basic conditions, the self-condensed products do not form in the reaction between ketones and benzaldehyde. The general reaction of Claisen–Schmidt condensation is...
01:08Esters to β-Ketoesters: Claisen Condensation Mechanism
Regular Claisen condensation involves the synthesis of β-ketoesters by combining identical ester molecules bearing two α hydrogens in the presence of an alkoxide base. The reaction commences with the deprotonation of the acidic α hydrogen by the base to form a resonance stabilized ester enolate. This nucleophilic ion then attacks the carbonyl center of another ester molecule to generate a tetrahedral alkoxide intermediate. Next, the expulsion of the alkoxide group from the intermediate restores...
01:20Sulfur Assimilation
Sulfur is an essential element in biological systems, contributing to synthesizing key biomolecules, including amino acids such as cysteine and methionine, and cofactors such as coenzyme A and biotin. Microorganisms primarily assimilate sulfur as sulfate (SO₄²⁻) from the environment, which must undergo a series of biochemical transformations before it can be incorporated into cellular components. As sulfate is highly oxidized, it must undergo assimilatory sulfate reduction to become...
01:29Biosynthesis of Lipids
Microbial membranes exhibit remarkable diversity in lipid composition, reflecting evolutionary adaptations to various environmental conditions. The three domains of life—Bacteria, Archaea, and Eukarya—synthesize membrane lipids through distinct biosynthetic pathways, leading to fundamental structural differences that impact membrane stability, function, and adaptability.Fatty Acid-Based Lipids in Bacteria and EukaryaBacteria and eukaryotes share a common fatty acid biosynthesis pathway, which...