and expertise of the experimenters in order to obtain a com- plete and accurate description of the structural experiment. For example, the author can upload an XML ﬁle containing a Fourier Shell Correlation graph, used in determination of the resolution of the uploaded volume. In order to ensure an accurate representation of the ﬁnal volume on the publicly available summary pages for a given entry, depositors are encouraged to supply images to accompany their entries. Cura- tion of the deposition involves several checking steps, such as veriﬁcation of the integrity of the uploaded map and its format (CCP4) by visualizing it using a display program such as CHIMERA (http://www.cgl.ucsf.edu/chimera/). The accuracy of information relating to the experimental details given in the ‘header’ XML ﬁle is checked by suitable cross-referencing to reference data, such as hardware manufacturers, taxonomy, processing program names, etc. Finally, external cross- references to related databases are checked, including GO (15) (http://www.ebi.ac.uk/ego/), INTERPRO (16) (http:// www.ebi.ac.uk/interpro/), ICTVdb VIRUS database (http:// www.ncbi.nlm.nih.gov/ICTVdb) and PUBMED (http://www. ncbi.nlm.nih.gov/entrez/query.fcgi). As in the AutoDep tool, the results of curation are presented to the depositor through the EMDep web interface, enabling the depositor to view the ﬁnally annotated deposition in the same form as the original deposition. Once the author of the deposition has granted approval for any changes made during curation then the ‘header’ informa- tion for each entry is made available. Release options for the volume, structure factors or layer-line data are ‘hold for pub- lication’ or for periods of 1, 2 or 4 years. The current status of a particular deposition can be found on the EMDB area of the EBI FTP site (ftp://ftp.ebi.ac.uk/pub/databases/emdb/) or through the EMDB search tool, EMSearch (http://www.ebi.ac. uk/msd-srv/emsearch/). Summaries of data from EMDB depositions are presented in the form of atlas pages, which can also be accessed via the EMSearch tool. The rapid pace of development in the ﬁeld of cryo-EM suggests that comprehensive descriptions of the structures of whole cells and organelles in terms of the spatial arrange- ments of their molecular components may soon become rou- tine. In this event the storage of data from these techniques will be of growing importance in terms of allowing public access to the resulting 3D reconstructions and the experimental details of the investigation (17) and EMDep will be an important central repository for these data. It is encouraging that many scientiﬁc journals now require an EMD ID before they publish the manuscript. NMR The MSD group is involved in the Collaborative Computing Project for the NMR community (CCPN) (18), which aims to provide a standard model, related libraries (19) and applica- tions (6), for storage and handling of NMR data (http:// www.ebi.ac.uk/msd-srv/docs/NMR/main.html). Essentially, an NMR project stored within the CCPN framework has clearly deﬁned data elements that are consistent with each other. The MSD group has converted its internal library of ligands, small molecules and monomers to the CCPN frame- work, and this information is now the prime reference data for Nucleic Acids Research, 2006, Vol. 34, Database issue D289 creating molecules when using CCPN. During the conversion process, the data were rearranged to handle different protona- tion variants of the same chemical group, and extra informa- tion was added (e.g. atom sets that are relevant for NMR, and protons that are likely to exchange with water, commonly used atom and residue naming systems). The information on atom and residue naming systems that are commonly used in NMR were gathered and incorporated, mainly from the AQUA (20) library ﬁles and the BioMagResBank (http://www.bmrb.wisc. edu/). We have further extended and cleaned up this nam- ing system data, and although it is an integral part of the CCPN compound library (http://www.ebi.ac.uk/msd-srv/docs/ NMR/chemCompXml/main.html) we have now made separ- ate reference ﬁles available in tabulated and XML formats (http://www.ebi.ac.uk/msd-srv/docs/NMR/refData/main.html). These ﬁles are free to download and use, although we request that any changes or mistakes are reported so they can be fed back to the community. This library of atom naming systems was already extensively and successfully used within the CCPN framework during the RECOORD project (21). In this project, collaboration with the BioMagResBank, depos- ited NMR constraint ﬁles are made consistent with the depos- ited coordinate atoms (22). The structures for these molecules are then recalculated with the same protocol, allowing a better comparison between them. Overall, the involvement of the MSD in the CCPN project means that deposited CCPN ﬁles can be directly mined for consistent information on the molecular system. Based on this effort we will also develop an NMR component of the E-MSD database to store NMR data and relate it directly to the relevant PDB entries. OTHER MSD DEVELOPMENTS The SIFTS initiative (11) is intended to bring together various disparate bioinformatics resources, from the structural, sequence and related realms. The SIFTS data have been updated recently to include version information from UniProt, to ensure that the various residue-level mappings are properly assigned and tracked through different updates of the constitu- ent data resources. The MSD group is currently rolling out several new services or resources. MSDtemplate is a search system for a set of data on the local interactions of residues. MSDpisa is a new MSD service that is similar in scope to PQS (7). It aims to apply unit cell symmetry (for X-ray determined structures) to obtain possible quaternary structure. The service provides informa- tion on putative assemblies for PDB entries, as well as detailed data on the interactions at inter-molecule interfaces. The MSDmotif service provides information on known 3D hydrogen-bonded motifs. The MSD deposition systems and related tools continue to ensure that deposited data are consistent and of high quality, thereby improving the quality of data in a range of inter-related publicly accessible archives. ACKNOWLEDGEMENTS E-MSD gratefully acknowledges the support of the Wellcome Trust (GR062025MA), the EU (TEMBLOR, NMRQUAL and 3D-EM NoE), CCP4, the BBSRC, the MRC and EMBL.