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Un ensamblaje atípico de AAA + ATPase controla la transposición eficiente a través de la remodelación del ADN y el

Ernesto Arias-Palomo¹, James M Berger¹

¹Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.

|August 16, 2015

Resumen

Los transposones utilizan las ATPasas AAA+ reguladoras para su función. Los investigadores descubrieron que el transposón IS21

Área de la Ciencia:

Biología molecular
Biología estructural
La genética

Sus antecedentes:

Los transposones son elementos genéticos móviles que influyen en la evolución del genoma y las enfermedades.
Muchos transposones dependen de las ATPasas AAA+ para su actividad.
El sistema de transposones IS21 incluye la AAA+ ATPasa IstB y la transposasa IstA.

Objetivo del estudio:

Para aclarar la base estructural y mecanicista de la regulación del transposón IS21 por su AAA + ATPasa, IstB.
Comprender cómo el IstB interactúa con el ADN y facilita la transposición.

Principales métodos:

Cristalografía de rayos X
Microscopía criolectrónica (cryo-EM)
Ensayos bioquímicos

Principales resultados:

IstB forma una estructura de caparazón decameric, que une el ADN e induce un agudo giro en U.
El complejo IstB•DNA es reconocido por la transposasa IS21, IstA.
El IstA estimula la hidrólisis del ATP por el IstB, lo que lleva al desmontaje complejo.

Conclusiones:

Este estudio revela un nuevo mecanismo de ensamblaje de orden superior y manipulación del ADN por una ATPasa AAA+.
Los hallazgos sugieren un modelo en el que la flexión de ADN mediada por IstB prepara los sitios de inserción para la transposición.

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