Video Experimental Relacionado
Updated: Jan 23, 2026
09:12
DNAzyme-dependent Analysis of rRNA 2’-O-Methylation
Published on: September 16, 2019
8.8K
Base estructural para la metilación iterativa por una enzima radicalaria dependiente de cobalamina
Jiayuan Cui1,2, Bo Wang1,2,3, Ravi K Maurya1,2
1Department of Chemistry, The Pennsylvania State University, University Park, PA 16802.
Resumen
Las cistobactamidas son inhibidores antibacterianos de la ADN girasa. Estudios estructurales revelan cómo la enzima CysS dependiente de Cbl utiliza S-adenosilmetionina (SAM) para la metilación iterativa del sustrato y la metilación de cob(I)alamina.
Área de la Ciencia:
- Bioquímica
- Biología Estructural
- Química de Productos Naturales
Sus antecedentes:
- Las cistobactamidas son potentes agentes antibacterianos dirigidos a la ADN girasa.
- Su estructura presenta porciones de ácido para-aminobenzoico con diversos grupos alcoxi cruciales para la actividad.
- Estos grupos alcoxi se forman por metilaciones iterativas catalizadas por la enzima CysS dependiente de cobalamina (Cbl), utilizando S-adenosilmetionina (SAM).
Objetivo del estudio:
- Elucidar el mecanismo de CysS en la catálisis de la metilación de cob(I)alamina y la metilación iterativa del sustrato.
- Comprender cómo CysS acomoda sustratos y productos durante reacciones de metilación secuenciales.
- Investigar la base estructural de las actividades catalíticas duales de CysS que involucran procesos polares SN2 y de radicales.
Principales métodos:
- Cristalografía de rayos X de un homólogo de CysS de Corallococcus sp. CA054B.
- Determinación de la estructura en presencia de sustratos que contienen metoxi y etoxi.
- Determinación de la estructura en ausencia de sustrato.
Principales resultados:
- Las estructuras revelan cómo CysS se une a sustratos y productos durante la O-alquilación iterativa.
- Una estructura libre de sustrato muestra cambios conformacionales en la unión de SAM, facilitando la metilación de cob(I)alamina.
- La enzima acomoda distintos pasos catalíticos que involucran mecanismos polares SN2 y de radicales.
Conclusiones:
- CysS emplea distintas conformaciones estructurales para facilitar tanto la metilación de cob(I)alamina como la metilación iterativa del sustrato.
- La comprensión del mecanismo de CysS proporciona información sobre la biosíntesis de productos naturales complejos.
- Los datos estructurales pueden informar el diseño de nuevos agentes antibacterianos dirigidos a la ADN girasa.
Videos de Conceptos Relacionados
01:07Radicals: Electronic Structure and Geometry
5.0K
This lesson delves into the geometry of a radical, which is influenced by the electronic structure of the molecule. The principle is similar to that of a lone pair, where the unpaired electron influences the geometry at the radical center.
Accordingly, the structure of a trivalent radical lies between the geometries of carbocations and carbanions. An sp2-hybridized carbocation is trigonal planar, while an sp3-hybridized carbanion is trigonal pyramidal. Here, the difference in geometry is...
Accordingly, the structure of a trivalent radical lies between the geometries of carbocations and carbanions. An sp2-hybridized carbocation is trigonal planar, while an sp3-hybridized carbanion is trigonal pyramidal. Here, the difference in geometry is...
5.0K
01:24Biosynthesis in Bacteria
587
Biosynthesis in bacteria is a fundamental anabolic process that generates essential macromolecules, including proteins, nucleic acids, lipids, and polysaccharides. These macromolecules are critical for cellular growth, replication, and function. The process is tightly regulated and energetically linked to catabolic pathways to ensure optimal resource utilization.Biosynthetic pathways begin with precursor metabolites such as pyruvate, acetyl-CoA, and glucose-6-phosphate derived from glycolysis,...
587
01:26Biosynthesis of Polysaccharides
577
Polysaccharides such as glycogen and starch are synthesized from nucleoside diphosphate sugars, primarily uridine diphosphate glucose (UDPG) and adenosine diphosphate glucose (ADPG). These activated glucose donors act as key intermediates in carbohydrate metabolism and biosynthesis. UDPG primarily involves glycogen synthesis in animals and many bacteria, while ADPG plays a fundamental role in starch synthesis in plants and certain bacteria.UDPG is formed when glucose-1-phosphate reacts with...
577
01:29Biosynthesis of Lipids
552
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...
552
01:28Biosynthesis of Nucleic Acids
1.0K
Nucleic acid biosynthesis is a fundamental biochemical process that produces the purine and pyrimidine nucleotides essential for DNA and RNA synthesis. This pathway maintains a balanced nucleotide pool, preventing imbalances that could jeopardize genetic integrity and cellular function. Given the crucial role of nucleotides, their synthesis is tightly regulated to ensure proper cellular homeostasis.Purine BiosynthesisThe biosynthesis of purine nucleotides begins with ribose-5-phosphate, a...
1.0K
02:34Enzymes
93.9K
Inside living organisms, enzymes act as catalysts for many biochemical reactions involved in cellular metabolism. The role of enzymes is to reduce the activation energies of biochemical reactions by forming complexes with its substrates. The lowering of activation energies favor an increase in the rates of biochemical reactions.
Enzyme deficiencies can often translate into life-threatening diseases. For example, a genetic abnormality resulting in the deficiency of the enzyme G6PD...
Enzyme deficiencies can often translate into life-threatening diseases. For example, a genetic abnormality resulting in the deficiency of the enzyme G6PD...
93.9K