Exon Junction Complex Electron Microscope Data

<p>The exon junction complex (EJC) is a macromolecular complex deposited at splice junctions on mRNAs as a consequence of splicing. At the core of the EJC are four proteins: eIF4AIII, a member of the DExH/D-box family of NTP-dependent RNA binding proteins, Y14, Magoh, and MLN51. These proteins form a stable heterotetramer that remains bound to the mRNA throughout many different cellular environments. We have determined the three-dimensional (3D) structure of this EJC core using negative-stain random-conical tilt electron microscopy. This structure represents the first structure of a DExH/D-box protein in complex with its binding partners. The EJC core is a four-lobed complex with a central channel and dimensions consistent with its known RNA footprint of about ten nucleotides. Using known X-ray crystallographic structures and a model of three of the four components, we propose a model for complex assembly on RNA and explain how Y14:Magoh may influence eIF4AIII's RNA binding</p><h3>Data description</h3><p>Linked to the right is a <a>reconstruction</a> of the exon junction complex core (EJC) in <a href="http://www.ccp4.ac.uk/html/maplib.html#description">MRC/CCP4 format</a> at about 25 Å resolution. The reconstruction was calculated from 9,655 images of negatively stained particles that were collected at 120 kV on a Philips CM12 electron microscope at 60,000 magnification, resulting in a pixel size of 1.17 Å.</p>