title: The Electron Microscopy eXchange (EMX) initiative.
abstract: Three-dimensional electron microscopy (3DEM) of ice-embedded samples allows the structural analysis of large biological macromolecules close to their native state. Different techniques have been developed during the last forty years to process cryo-electron microscopy (cryo-EM) data. Not surprisingly, success in analysis and interpretation is highly correlated with the continuous development of image processing packages. The field has matured to the point where further progress in data and methods sharing depends on an agreement between the packages on how to describe common image processing tasks. Such standardization will facilitate the use of software as well as seamless collaboration, allowing the sharing of rich information between different platforms. Our aim here is to describe the Electron Microscopy eXchange (EMX) initiative, launched at the 2012 Instruct Image Processing Center Developer Workshop, with the intention of developing a first set of standard conventions for the interchange of information for single-particle analysis (EMX version 1.0). These conventions cover the specification of the metadata for micrograph and particle images, including contrast transfer function (CTF) parameters and particle orientations. EMX v1.0 has already been implemented in the Bsoft, EMAN, Xmipp and Scipion image processing packages. It has been and will be used in the CTF and EMDataBank Validation Challenges respectively. It is also being used in EMPIAR, the Electron Microscopy Pilot Image Archive, which stores raw image data related to the 3DEM reconstructions in EMDB.
authors.affiliation: Escuela Politecnica Superior, Universidad Autonoma de Madrid, Campus Universidad Autonoma, 28049 Cantoblanco, Madrid, Spain. Electronic address: roberto@cnb.csic.es.
authors.forename: Roberto
authors.initials: R
authors.lastname: Marabini
authors.affiliation: National Center for Macromolecular Imaging, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Ludtke
authors.affiliation: Graduate Program in Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, TX 77030 USA.
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Murray
authors.affiliation: National Center for Macromolecular Imaging, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA.
authors.forename: Wah
authors.initials: W
authors.lastname: Chiu
authors.affiliation: Biocomputing Unit, National Center for Biotechnology (CSIC), c/Darwin, 3, Campus Universidad Autónoma, 28049 Cantoblanco, Madrid, Spain.
authors.forename: Jose M
authors.initials: JM
authors.lastname: de la Rosa-Trevín
authors.affiliation: European Molecular Biology Laboratory - European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK.
authors.forename: Ardan
authors.initials: A
authors.lastname: Patwardhan
authors.affiliation: Laboratory of Structural Biology Research, National Institute of Arthritis, Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: J Bernard
authors.initials: JB
authors.lastname: Heymann
authors.affiliation: Biocomputing Unit, National Center for Biotechnology (CSIC), c/Darwin, 3, Campus Universidad Autónoma, 28049 Cantoblanco, Madrid, Spain.
authors.forename: Jose M
authors.initials: JM
authors.lastname: Carazo
mesh_terms: D000465:Algorithms; D020285:Cryoelectron Microscopy / Q000295:instrumentation / Q000592:standards*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000592:standards* / Q000706:statistics & numerical data; D033181:Information Dissemination; D012984:Software / Q000592:standards*
keywords: Conventions; Data sharing; Electron microscopy; Standardization