Video Experimental Relacionado
Updated: Dec 30, 2025
08:51
Coulomb Explosion Imaging as a Tool to Distinguish Between Stereoisomers
Published on: August 18, 2017
10.8K
La cristalografía de rayos X y las propiedades quirópticas inesperadas reasignan la configuración de la
Hong-Bing Liu1, Gregory H Imler2, Kim K Baldridge3
1Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases , National Institutes of Health , Bethesda , Maryland 20892-0820 , United States.
Journal of the American Chemical Society
|January 28, 2020
Resumen
Las esponjas marinas producen los productos naturales bis-indanos haliclonadiamina y papuamina. La cristalografía de rayos X revela configuraciones estereoquímicas distintas, desafiando las suposiciones anteriores y provocando una reasignación estructural para la haliclonadiamina.
Área de la Ciencia:
- Química de los productos naturales marinos
- Química orgánica
- Biología estructural
Sus antecedentes:
- La haliclonadiamina y la papuamina son productos naturales marinos bisindanos obtenidos de la esponja Haliclona sp.
- Estudios anteriores sugirieron que sus estructuras diferían solo por una inversión estereocéntrica.
- Estos compuestos exhiben una compleja estereoquímica y tienen un potencial significado biológico.
Objetivo del estudio:
- Determinar con precisión la estereoquímica absoluta de la haliclonadiamina y la papuamina mediante el uso de la cristalografía de rayos X.
- Investigar las similitudes conformacionales y las propiedades quirópticas de estos productos naturales marinos relacionados.
- Explorar los orígenes biosintéticos y las relaciones estereocímicas de estos compuestos dentro de la esponja.
Principales métodos:
- Se empleó la cristalografía de rayos X para dilucidar las estructuras tridimensionales precisas y las configuraciones absolutas.
- Se utilizaron cálculos de dicroísmo circular electrónico (ECD) y mediciones experimentales para analizar las propiedades quirópticas.
- Análisis de múltiples muestras de esponjas de diversas ubicaciones e identificación de precursores biosintéticos.
Principales resultados:
- La cristalografía de rayos X reveló diferencias significativas en la estereoquímica entre la papuamina (1R,3S,8R,9S,14S,15R,20S,22R) y la haliclonadiamina (1S,3R,8S,9R,14R,15S,20R,22R).
- Ambos compuestos adoptan conformaciones macrocíclicas similares, con el dieno dentro del macrociclo que domina el ECD.
- La haliclonadiamina y la papuamina se encuentran consistentemente como un par relacionado en diferentes ubicaciones geográficas.
- Se aisló un precursor biosintético, la halicondriamina C, que proporcionó información sobre su formación.
Conclusiones:
- El estudio requiere una reasignación de la estructura de la haliclonadiamina basada en datos cristalográficos definitivos.
- El núcleo macrocíclico influye significativamente en los espectros de ECD observados para ambos compuestos.
- La coincidencia constante y la compleja relación estereocímica entre la haliclonadiamina y la papuamina plantean dudas sobre su biosíntesis.
Más Videos Relacionados
11:27X-Ray Crystallography to Study the Oligomeric State Transition of the Thermotoga maritima M42 Aminopeptidase TmPep1050
Published on: May 13, 2020
4.3K
06:35Construction and Systematical Symmetric Studies of a Series of Supramolecular Clusters with Binary or Ternary Ammonium Triphenylacetates
Published on: February 15, 2016
8.4K
Videos de Conceptos Relacionados
02:05Prochirality
4.8K
The concept of prochirality leads to the nomenclature of the individual faces of a molecule and plays a crucial role in the enantioselective reaction. It is a concept where two or more achiral molecules react to produce chiral products. A typical process is the reaction of an achiral ketone to generate a chiral alcohol. Here, the achiral reactant reacts with an achiral reducing agent, sodium borohydride, to generate an equimolar mixture of the chiral enantiomers of the product. For example, an...
4.8K
01:19Structure of Amines
3.1K
The hybridized nitrogen atom in amines possesses a lone pair of electrons and is bound to three substituents with a bond angle of around 108°, which is less than the tetrahedral angle of 109.5°. However, the C–N–H bond angle is slightly larger at 112°, with a carbon–nitrogen bond length of 147 pm. This carbon–nitrogen bond length of of amines is longer than the carbon–oxygen bond of alcohols (143 pm) but shorter than alkanes’ carbon–carbon bond (154 pm). These aspects are...
3.1K
02:30Chirality at Nitrogen, Phosphorus, and Sulfur
6.7K
Chirality is most prevalent in carbon-based tetrahedral compounds, but this important facet of molecular symmetry extends to sp3-hybridized nitrogen, phosphorus and sulfur centers, including trivalent molecules with lone pairs. Here, the lone pair behaves as a functional group in addition to the other three substituents to form an analogous tetrahedral center that can be chiral.
A consequence of chirality is the need for enantiomeric resolution. While this is theoretically possible for all...
A consequence of chirality is the need for enantiomeric resolution. While this is theoretically possible for all...
6.7K
02:30Chirality in Nature
16.3K
Chirality is the most intriguing yet essential facet of nature, governing life’s biochemical processes and precision. It can be observed from a snail shell pattern in a macroscopic world to an amino acid, the minutest building block of life. Most of the snails around the world have right-coiled shells because of the intrinsic chirality in their genes. All the amino acids present in the human body exist in an enantiomerically pure state, except for glycine - the sole achiral amino acid.
16.3K
02:18X-ray Crystallography
25.6K
The size of the unit cell and the arrangement of atoms in a crystal may be determined from measurements of the diffraction of X-rays by the crystal, termed X-ray crystallography.
Diffraction
Diffraction is the change in the direction of travel experienced by an electromagnetic wave when it encounters a physical barrier whose dimensions are comparable to those of the wavelength of the light. X-rays are electromagnetic radiation with wavelengths about as long as the distance between neighboring...
Diffraction
Diffraction is the change in the direction of travel experienced by an electromagnetic wave when it encounters a physical barrier whose dimensions are comparable to those of the wavelength of the light. X-rays are electromagnetic radiation with wavelengths about as long as the distance between neighboring...
25.6K
02:52Stereoisomerism
13.7K
Isomerism in Complexes
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...
13.7K