Video Experimental Relacionado
Updated: Jun 25, 2026
14:44
Structure and Coordination Determination of Peptide-metal Complexes Using 1D and 2D 1H NMR
Published on: December 16, 2013
La asimetría en los espectros 13C-13C COSY proporciona información sobre la geometría de los ligandos en las
Ivano Bertini1, Beatriz Jiménez, Mario Piccioli
1Magnetic Resonance Center, University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy. ivanobertini@cerm.unifi.it
Journal of the American Chemical Society
|September 1, 2005
Resumen
La Resonancia Magnética Nuclear (RMN) utilizando espectros COSY de carbono-13 (13C) cuantifica las distancias de metal a carbono en las proteínas. Este método identifica los grupos de coordinación de metales y los modos de unión al carboxilato en la calbindina D9k sustituida por cerio.
Área de la Ciencia:
- Química biofísica y bioquímica.
- Biología Estructural Biología estructural.
- Espectroscopia de resonancia magnética nuclear Espectroscopia de resonancia magnética nuclear Espectroscopia de resonancia magnética nuclear Espectroscopia de resonancia magnética nuclear Espectroscopia de resonancia magnética nuclear
Sus antecedentes:
- La espectroscopia de Resonancia Magnética Nuclear (RMN) es crucial para determinar la estructura y dinámica de las proteínas.
- Los efectos de relajación paramagnética en RMN pueden proporcionar información sobre las distancias entre los espines y los iones metálicos.
- La comprensión de las interacciones metal-ligando es clave en la investigación de las metaloproteínas.
Objetivo del estudio:
- Investigar la utilidad de los espectros homonucleares 13C COSY para cuantificar las distancias metal-carbono en las proteínas.
- Para identificar grupos de coordinación de metales y determinar los modos de unión de metales en las metaloproteínas utilizando RMN.
- Para aplicar este método a la proteína de dicalcio sustituida por cerio, la calbindina D9k.
Principales métodos:
- Adquisición y análisis de espectros homonucleares 13C COSY.
- Análisis cuantitativo de las intensidades de pico cruzado de Calpha-C'.
- Explotación de los efectos de relajación paramagnética inducidos por un centro metálico.
- Aplicación a la calbindina D9k. sustituida por el cerio.
Principales resultados:
- La intensidad relativa de los picos cruzados de Calpha-C' en los espectros COSY 13C se correlaciona con las distancias de metal a carbono.
- Los efectos de relajación paramagnética permitieron la identificación directa de los grupos de coordinación de metales.
- Los modos de unión al carboxilato monodentado y al carboxilato bidentado se distinguieron directamente a través de RMN.
Conclusiones:
- El análisis cuantitativo de los espectros 13C COSY es una herramienta poderosa para las mediciones de distancia en metaloproteínas.
- Este enfoque de RMN facilita la identificación de las interacciones metal-ligando y los modos de unión.
- El estudio caracterizó con éxito la coordinación metálica en la calbindina D9k.
Más Videos Relacionados
12:47Nuclear Magnetic Resonance Spectroscopy for the Identification of Multiple Phosphorylations of Intrinsically Disordered Proteins
Published on: December 27, 2016
14:55Atomic Scale Structural Studies of Macromolecular Assemblies by Solid-state Nuclear Magnetic Resonance Spectroscopy
Published on: September 17, 2017
Videos de Conceptos Relacionados
01:02¹H NMR: Interpreting Distorted and Overlapping Signals
Spin systems where the difference in chemical shifts of the coupled nuclei is greater than ten times J are called first-order spin systems. These nuclei are weakly coupled, and their chemical shifts and coupling constant can generally be estimated from the well-separated signals in the spectrum.
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are slanted or...
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are slanted or...
01:10Carbon-13 (¹³C) NMR: Overview
Carbon-13 is a naturally occurring NMR-active isotope of carbon with a low natural abundance of 1.1%. In contrast, carbon-12 is the most abundant isotope of carbon with zero nuclear spin. Therefore, it is NMR inactive. The gyromagnetic ratio of carbon-13 is smaller than that of protons. As a result, carbon-13 resonance is about 6000 times weaker than proton resonance. For a given magnetic field strength, the resonance frequency of carbon-13 is about one-fourth of the resonance frequency for...
01:062D NMR: Homonuclear Correlation Spectroscopy (COSY)
Homonuclear correlation spectroscopy, or COSY, is a 2-dimensional NMR technique that provides information about coupled protons. Typically, the geminal and vicinal coupling are observed. For example, consider the COSY spectrum of ethyl acetate, where its 1D proton NMR spectrum is plotted along the vertical and horizontal axes with their corresponding chemical shift scale. Three spots on the diagonal corresponding to the three peaks in the 1D proton spectrum are called diagonal peaks. The COSY...
01:08NMR Spectroscopy: Spin–Spin Coupling
The spin state of an NMR-active nucleus can have a slight effect on its immediate electronic environment. This effect propagates through the intervening bonds and affects the electronic environments of NMR-active nuclei up to three bonds away; occasionally, even farther. This phenomenon is called spin–spin coupling or J-coupling. Coupling interactions are mutual and result in small changes in the absorption frequencies of both nuclei involved. While nuclei of the same element are involved in...
01:04¹³C NMR: ¹H–¹³C Decoupling
The probability of having two carbon-13 atoms next to each other is negligible because of the low natural abundance of carbon-13. Consequently, peak splitting due to carbon-carbon spin-spin coupling is not observed in spectra. However, protons up to three sigma bonds away split the carbon signal according to the n+1 rule, resulting in complicated spectra.
A broadband decoupling technique is used to simplify these complex, sometimes overlapping, signals. Broadband decoupling relies on a...
A broadband decoupling technique is used to simplify these complex, sometimes overlapping, signals. Broadband decoupling relies on a...
01:162D NMR: Overview of Homonuclear Correlation Techniques
Homonuclear correlation spectroscopy (COSY) is a powerful technique used in Nuclear Magnetic Resonance (NMR) spectroscopy to study the correlations between nuclei of the same type within a molecule. It provides information about scalar couplings between adjacent nuclei, which helps determine connectivity and structural information. There are several COSY variants, each with its unique strengths and experimental parameters.
COSY90 is the standard two-dimensional (2D) COSY experiment that...
COSY90 is the standard two-dimensional (2D) COSY experiment that...