Bioinformatics analysis of data produced by high-throughput biology, for instance genome projects, is one of the major challenges for the next years. Some of the requirements of this analysis are to access up-to-date databanks (of sequences, patterns, 3D structures, etc.) and relevant algorithms (for sequence similarity, multiple alignment, pattern scanning, etc.). GPS@ is a Web portal devoted to bioinformatics applications on the grid (Grid Protein Sequence Analysis, http://gpsa-pbil.ibcp.fr). GPS@ is the grid release of the NPS@ bioinformatics portal, and is wrapping the mechanisms required for submitting bioinformatics analyses on the grid infrastructure. For example, we have put online two multiple alignment Web Services that are submitting the computing job on a remote grid environment. One is accessible through a classical Web interface by using a simple Web browser; the other one can be used through a SOAP and workflow client such as Taverna or Triana. These Web services can process the submitted alignment on two different computing environments: a local and classical one which is a cluster of 30 CPUs, but we are also providing biologists with a large-scale distributed one: the grid platform of the EU-EGEE project (more than 20,000 CPUs available at the European scale).