The C6 (Comparison of Crystallisation Conditions at the Collaborative Crystallisation Centre) webtool is an online resource developed and supported by the Biomolecular Crystallisation and Characterisation laboratory at the CSIRO. The BCC evolved from the long-running Collaborative Crystallisation Centre (C3) which supported Melbourne's structural biology community for over 14 years.
The C6 Webtool was built to help protein crystallographers rationally compare and select appropriate crystallisation screens for their experiments. The concept of the tool, its development, and the comparison and distance metrics used to assess screens are primarily the work of Janet Newman, Brian Lawson, and Vincent Fazio. Recently, C6 has undergone a significant overhaul and been rewritten to add new features, improve readability and accessibility, and to interact with a RockMaker database. The original condition comparison algorithms and metrics have been retained. We hope to showcase the new and improved functions of C6, and encourage the wider protein crystallisation community to use this resource.
The webtool has four main modules available to help protein crystallographers rationally compare and select appropriate crystallisation screens for their experiments. The Search module allows users to find screens similar to a specified screen, based on the C6 distance metric; search for screens containing a specific chemical (ingredient); and search for screens which contain a specified condition (or similar conditions). The Compare module allow users to compare the similarity of two screens or two specified screen well conditions. The Screens module displays information about the screens available in the associated RockMaker database; can be filtered by vendor or vendor sub-category; and can sort screens by attributes (such as internal diversity, average pH, and primary ingredients). Finally, the Ingredients module displays information about the ingredients registered in the database, including stock details, titration curves, CAS numbers, and aliases.