Kevin Cowtan, University of York, August 2007. Last updated September 2007.

Colophon Sequins were gold coins used in the persion gulf during the middle ages. The name derives from the Arabic sikka, meaning coin. They were sometimes sown into clothes, giving rise to the modern usage.
'sequins' detects sequence insertions.

'sequins' performs sequence validation by comparing the model side chains against the electron density. It may be run with phases from experimental phasing, or it can calculate its own phases using a side-chain-omit process. In this case it can be used after molecular replacement, or to validate structures in the PDB.

The latest version of the software is available through the CCP4 update system.

The installer will create a new task in the 'Validation and Depostition' menu, labelled 'Sequence validation'.


How to run Sequins

A set of reference structure will have been provided with the program. The structure 1TQW is good for typical protein problems at resolutions up to 1.25A, although in practice including data much beyond 2.0A doesn't make much difference. For exotic cases you might want to provide your own reference structures.

Open the 'Validation and Deposition' module in CCP4I, and select the 'Sequence validation'. Enter your mtz and pdb files, and click 'Run'

Latest News

Speed improvements and bug fixes.
Initial release.