MOTIVATION: Post-translational modification by the Small Ubiquitin-like Modifier 
(SUMO) proteins, a process termed SUMOylation, is involved in many fundamental 
cellular processes. SUMO proteins are conjugated to a protein substrate, 
creating an interface for the recruitment of cofactors harboring 
SUMO-interacting motifs (SIMs). Mapping both SUMO-conjugation sites and SIMs is 
required to study the functional consequence of SUMOylation. To define the best 
candidate sites for experimental validation we designed JASSA, a Joint Analyzer 
of SUMOylation site and SIMs.
RESULTS: JASSA is a predictor that uses a scoring system based on a Position 
Frequency Matrix derived from the alignment of experimental SUMOylation sites or 
SIMs. Compared with existing web-tools, JASSA displays on par or better 
performances. Novel features were implemented towards a better evaluation of the 
prediction, including identification of database hits matching the query 
sequence and representation of candidate sites within the secondary structural 
elements and/or the 3D fold of the protein of interest, retrievable from 
deposited PDB files.
AVAILABILITY AND IMPLEMENTATION: JASSA is freely accessible at 
http://www.jassa.fr/. Website is implemented in PHP and MySQL, with all major 
browsers supported.
CONTACT: guillaume.beauclair@inserm.fr
SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics 
online.