What is EMPIAR?


What is EMPIAR?

EMPIAR, the Electron Microscopy Public Image Archive, is a free public resource for raw, 2D electron microscopy (EM) images (1).

Why do we need EMPIAR?

EMPIAR provides a way to easily access state-of-the-art 2D image data that underpins 3D cryo-EM structures of biomacromolecules and molecular machines. It complements the Electron Microscopy Data Bank (EMDB), where corresponding 3D structures are stored, and PDB which stores atomic models of macromolecular structures (Figure 1). EMPIAR data has been used to facilitate development and validation of methods, which will lead to better 3D structures.

Distribution of data between archives.

Figure 2 Distribution of data between archives.

The development of EMPIAR was prompted by calls from the electron microscopy community on the urgent need for archiving of raw image data related to EMDB structures. Notably, two workshops run by the EMBL-EBI and the Open Microscopy Environment (OME) kickstarted the process (2, 3) and in 2014 the EMBL-EBI received funding to develop the resource.

EMPIAR has been designed to handle very large datasets with sizes in the terabyte range. EMPIAR uses Aspera software plugin to enable the safe transfer of large datasets. As of February 2017 EMPIAR contains 67 entries averaging ~700 GB in size, with nine entries exceeding 1 TB.