Dear all,
The generation of reliable restraints for novel small-molecule
ligands in macromolecular complexes is of great importance for both ligand
placement into density maps and subsequent refinement. This has led us to
develop Grade, a ligand restraint generator whose main source of restraint
information is the Cambridge Structural Database (CSD) of small-molecule
crystal structures, queried using the MOGUL program developed by the CCDC.
Where small-molecule information is lacking, Grade uses quantum chemical
procedures to obtain the restraint values.
Grade was released to academic users as part of the BUSTER package in
July 2011 and has proved popular. However, a problem for numerous academic
users has been that, in order to get the best restraints from Grade, a CSD
system licence is necessary to make use of MOGUL. Although many institutions
already have CSD site licences, and otherwise licences are available at a
reasonable cost, this has prevented the use of Grade by small groups and
occasional users.
To provide easy access to Grade, the CCDC has kindly agreed that we
can provide a public Web server that includes the use of MOGUL in its
invocation of Grade. The first version of the server is now available, free
of charge, at
http://grade.globalphasing.org
We hope this server will prove useful to academic users. We will be
very grateful for any feedback you might be able to provide about this
server, so that we can keep improving it to meet the needs of the community.
Please send us your feedback and comments at
buster-deve...@globalphasing.com
rather than write to a specific developer.
With best wishes,
The Global Phasing developers: Gerard Bricogne, Claus Flensburg,
Peter Keller, Wlodek Paciorek, Andrew Sharff, Oliver Smart,
Clemens Vonrhein and Thomas Womack.
