History and Constitution
The Collaborative Computational Project Number 4 in Protein Crystallography was set up in 1979 to support collaboration between researchers working on such software in the UK, and to assemble a comprehensive collection of software to satisfy the computational requirements of the relevant UK groups. The results of this effort gave rise to the CCP4 program suite, which is distributed to academic and commercial users world-wide.
CCP4 was initially supported by the UK Science and Engineering Research Council (SERC), and currently by the Biotechnology and Biological Sciences Research Council (BBSRC). The project is hosted by the Scientific Computing Department of STFC at its Rutherford Laboratory.
Philosophy of the CCP4 Suite
The CCP4 software is accessed via a central graphical interface. The CCP4 suite consists of a set of separate programs that communicate via standard format data files. It is hence very easy to add new programs to the suite, or to modify existing ones without disrupting other sections of the suite. Converting a program to use the standard CCP4 file formats is straightforward.
The philosophy of the collection has been to be inclusive, so that several programs may be available to do the same task. The components of CCP4 are thus a collection of programs using a standard software library to access standard format files, and is available for Linux, Windows and Mac OS X. Programs are mostly written in C, C++, Fortran and Python.
To use the programs the user must assign input and output files, and run the programs; in the graphical interface most in- and output files are automatically assigned. Often an output file becomes the input to the next step. Called from a command line, system parameter substitution may be used to create filenames in a systematic way; a command file may be used to call a sequence of calculations.
Standard file formats are defined for the principal data types used in crystallography: reflection data; density maps; and atomic coordinates. In defining these formats, a number of trade-offs are made between efficiency (in space and access time), flexibility, portability, and simplicity of use.
There is a policy of continual technical and scientific updates to the suite. Where existing programs have been incorporated they have often subsequently undergone considerable enhancement above that needed to use the CCP4 file formats.
CCP4 is overseen by three committees:
- Working Group 1 meets annually at the Study Weekend and makes general policy. PIs / EOs in all UK protein crystallography groups (Research council laboratory or charity funded or eligible to hold a structural biology grant) are invited to WG1, as well as representatives of UK-based commercial groups.
- Working Group 2 presents a forum for active crystallographic representatives of the WG1 group or developers and facilitates exchange of information. WG2 oversees the activities of CCP4 to organise and/or sponsor meetings and organises the two-day Study Weekend (SW).
- The Executive Committee comprises the Chairs of Working Groups 1 and 2, the CCP4 Group Leader and elected individuals from Working Group 1. The Executive Committee oversees the project on a day-to-day basis and reports back to Working Group 1.
Current members of the Executive Committee and of current developers are found on the People Page.
Licensing and Referencing
There are separate licences for academic and commercial groups, see Licensing Page.
Any publication arising from use of the CCP4 software suite should include both references to the specific programs used (see the References section of the distributed documentation) and the following reference to the CCP4 suite:
- D. Winn et al. Acta. Cryst. D67 , 235-242 (2011) – “Overview of the CCP4 suite and current developments” [ doi:10.1107/S0907444910045749 ] reprint in PDF format Copyright © International Union of Crystallography.
Such citations are vital to the CCP4 project, and individual program authors, in maintaining funding and thus being able to develop CCP4 further. Many relevant articles can be found in the proceedings of the 2017 Study Weekend, published as special issue of Acta Cryst D. [update the link Part 1 http://journals.iucr.org/d/issues/2018/02/00/ and Part 2: http://journals.iucr.org/d/issues/2018/03/00/]