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Updated: Feb 13, 2026
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LERLIC-MS/MS for In-depth Characterization and Quantification of Glutamine and Asparagine Deamidation in Shotgun Proteomics
Published on: April 9, 2017
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La transferasa O-GlcNAc reconoce sustratos de proteínas utilizando una escalera de asparagina en la superhélice de
Zebulon G Levine1, Chenguang Fan1, Michael S Melicher1
1Department of Microbiology and Immunobiology , Harvard Medical School , Boston , Massachusetts 02115 , United States.
Journal of the American Chemical Society
|February 28, 2018
Resumen
La enzima O-GlcNAc Transferasa (OGT) utiliza una escalera de asparagina en su dominio TPR para reconocer y glicosilizar sustratos de proteínas. Este hallazgo aclara la forma en que la OGT selecciona los objetivos para la O-GlcNAcilación.
Área de la Ciencia:
- La bioquímica
- Biología molecular
- Glicobiología
Sus antecedentes:
- La enzima O-GlcNAc Transferasa (OGT) modifica numerosas proteínas nucleares y del citoplasma.
- El mecanismo de reconocimiento del sustrato de la OGT sigue siendo en gran medida desconocido debido a la ausencia de una secuencia de consenso.
Objetivo del estudio:
- Investigar cómo OGT reconoce sus diversos sustratos de proteínas.
- Determinar el papel de la escalera de asparagina en el dominio de repetición de tetratricopéptido (TPR) de la OGT en la selección del sustrato.
Principales métodos:
- Desarrollo de un ensayo de microarrays de proteínas quimioenzimáticas para evaluar la actividad de la OGT en miles de proteínas.
- Mutagénesis dirigida al sitio de cinco residuos de asparagina dentro del dominio OGT TPR.
Principales resultados:
- La mutación de la escalera de asparagina redujo significativamente la capacidad de OGT para glicosilizar sustratos de proteínas en el microarray.
- La O-GlcNAcilación de sustratos proteicos en extractos celulares también se atenuó notablemente.
- OGT conservó actividad contra péptidos cortos, lo que sugiere que la escalera es crucial para el reconocimiento de proteínas.
Conclusiones:
- La escalera de asparagina dentro del dominio OGT TPR es esencial para reconocer la mayoría de sus sustratos proteicos.
- Esta interacción ocurre en el lumen TPR proximal al dominio catalítico.
- El estudio aclara un mecanismo clave para la especificidad del sustrato OGT.
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