The CCP4 (Collaborative Computational Project, Number 4) software suite is a collection of programs and associated data and software libraries which can be used for macromolecular structure determination by X-ray crystallography. The suite is designed to be flexible, allowing users a number of methods of achieving their aims. The programs are from a wide variety of sources but are connected by a common infrastructure provided by standard file formats, data objects and graphical interfaces. Structure solution by macromolecular crystallography is becoming increasingly automated and the CCP4 suite includes several automation pipelines. After giving a brief description of the evolution of CCP4 over the last 30 years, an overview of the current suite is given. While detailed descriptions are given in the accompanying articles, here it is shown how the individual programs contribute to a complete software package.

CCP4i is a graphical user interface that makes running programs from the CCP4 suite simpler and quicker. It is particularly directed at inexperienced users and tightly linked to introductory and scientific documentation. It also provides a simple project-management system and visualization tools. The system is readily extensible and not specific to CCP4 software.

The CCP4 molecular-graphics program now uses the Qt framework to provide a modern look and feel. There are many new features including rendering for publication-quality images and sequence alignment.

The X-ray laboratory at the University of North Carolina has been operating in its current format for over 15 years. In that time, structures have been determined using a variety of instruments, computer platforms and software packages. The data collection capabilities have expanded from dozens per year to hundreds per year and can only continue to increase. The result has been a volume of completed structures, many of which have not yet been published or deposited in the public databases. Over the years the computer data files have been saved, but little attempt, other than a reference number, has been made to allow users to search for old structures. This paper describes a project to save and categorize this data while the volume is still manageable, and provide a mechanism for future structures to be archived automatically. The main archive is a relational database with the choice of content based largely on the IUCr core CIF dictionary [1] augmented by a number of local fields. As a result, enough information is retained for each structure to permit the extraction of information required by journals with the most rigorous requirements. The main archive is only directly accessible to the system administrator and user access is via a software interface which exposes most of the database fields and a number of utilities that are based largely on the NRCVAX [2] software package. This permits the implementation of a security system which allows users to limit access to their structures as well as protecting the database from unauthorized or undocumented modification. As part of the archiving process a structure is passed through a validation procedure, similar to those employed by journals and public databases, which ensures consistency of the data and compares value ranges with those expected from a normal structure. This procedure also computes a number of fields that may be required, but are not normally produced by software, In order for the deposition to be finalized the user has either to correct any potential errors or provide an explanation which is stored with the entry. This ensures that if this structure is required at some point in the future for publication it will either pass any journal checks or the reason why not will be readily available. A number of tables are also generated that permit easy searching of the database for structures based on a number of structural or chemical criteria. The results of such a search permit an authorized user to extract the data for a structure. Utilities are provided to analyse such a structure and produce tables and graphics suitable for publication or inclusion in talks or presentations.[1] IUCr, (October 2003) http://www.iucr.org/iucrtop/cif/cif_core/index.html [2] Gabe, E

This new package will provide easy-to-use access to crystallographic structure solution, model building and structure analysis. It will be possible for any developer to integrate scienti®c software into the system.