Video Experimental Relacionado
Updated: Jul 5, 2026
14:44
Structure and Coordination Determination of Peptide-metal Complexes Using 1D and 2D 1H NMR
Published on: December 16, 2013
La proteína de resistencia al cobre PcoC coordina Cu(I) a través de nuevas interacciones S-metionina
Katrina Peariso1, David L Huffman, James E Penner-Hahn
1Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA.
Journal of the American Chemical Society
|January 9, 2003
Resumen
La proteína de resistencia al cobre de E. coli PcoC se une al cobre y a otros metales. Su estructura única revela un nuevo sitio de unión de cobre rico en metionina, crucial para la supervivencia bacteriana bajo estrés de cobre.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Química de las metaloproteínas.
- Mecanismos de resistencia microbiana a las resistencias microbianas.
Sus antecedentes:
- La proteína de resistencia al cobre de E. coli PcoC es vital para la supervivencia bacteriana bajo un alto estrés por cobre.
- PcoC presenta una secuencia única rica en metionina, lo que insinúa un papel no tradicional de la metionina en la unión del cobre.
- Estudios anteriores indicaron un pliegue de barril beta similar a las proteínas de cobre azul.
Objetivo del estudio:
- Para investigar las propiedades de unión a los metales y las características estructurales de la proteína E. coli PcoC.
- Para aclarar la química de coordinación del cobre dentro de la proteína PcoC, en particular el papel de los residuos de metionina.
- Comprender las diferencias estructurales entre las formas reducidas (Cu ((I)) y oxidadas (Cu ((II)) de PcoC.
Principales métodos:
- Espectroscopia de absorción de rayos X (XAS) para analizar la estructura del sitio de cobre en ambos estados de oxidación.
- Estudios cristalográficos de la proteína apo.
- Ensayos de unión a metales para determinar la afinidad de PcoC para Cu (I), Cu (II), Hg (II) y Ag (I).
Principales resultados:
- PcoC se une tanto a Cu (I) y Cu (II), así como a Hg (II) y Ag (I).
- Existen diferencias estructurales significativas entre los sitios Cu (II) y Cu (I) en PcoC, a diferencia de las típicas proteínas de cobre azul.
- Cu(II) PcoC exhibe una estructura tetragonal con ligandos de histidina, mientras que Cu(I) PcoC presenta un sitio trigonal coordinado por dos residuos de metionina.
Conclusiones:
- PcoC representa el primer ejemplo bien caracterizado de un sitio de unión al cobre de una proteína rica en metionina.
- Este descubrimiento revela un nuevo tipo de química de coordinación biológica del cobre.
- La ligadura única de metionina en PcoC es crítica para su función en la resistencia al cobre.
Videos de Conceptos Relacionados
03:45Formation of Complex Ions
A type of Lewis acid-base chemistry involves the formation of a complex ion (or a coordination complex) comprising a central atom, typically a transition metal cation, surrounded by ions or molecules called ligands. These ligands can be neutral molecules like H2O or NH3, or ions such as CN− or OH−. Often, the ligands act as Lewis bases, donating a pair of electrons to the central atom. These types of Lewis acid-base reactions are examples of a broad subdiscipline called coordination...
02:51Metal-Ligand Bonds
The hemoglobin in the blood, the chlorophyll in green plants, vitamin B-12, and the catalyst used in the manufacture of polyethylene all contain coordination compounds. Ions of the metals, especially the transition metals, are likely to form complexes.
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
02:34Structural Isomerism
Isomerism in Complexes
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can be...
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can be...
01:23Properties of Organometallic Compounds
Organometallic compounds are compounds that contain a carbon–metal bond. Carbon belongs to an organyl group like alkyl, aryl, allyl, or benzyl groups. The metal can be from Group I or Group II of the periodic table, a transition metal, or a semimetal.
01:17Precipitation and Co-precipitation
Precipitation and coprecipitation methods can be used to separate a mixture of ions in a solution. In qualitative inorganic analysis, ions that form sparingly soluble precipitates with the same reagent are separated based on the differences in solubility products. For example, consider the separation of Cu(II) and Fe(II) ions by precipitation as insoluble sulfides. First, copper(II) sulfide is precipitated by the addition of acidic H2S, where the dissociation of H2S is suppressed. Adding H2S...
00:56Extraction: Advanced Methods
Metal ions can be separated from one another by complexation with organic ligands–the chelating agent– to form uncharged chelates. Here, the chelating agent must contain hydrophobic groups and behave as a weak acid, losing a proton to bind with the metal. Since most organic ligands used in this process are insoluble or undergo oxidation in the aqueous phase, the chelating agent is initially added to the organic phase and extracted into the aqueous phase. The metal-ligand complex is formed in...