Soon and a new generation of scientific workbenches will be developed as a collaborative effort among various research institutions in the US. These scientific workbenches will be accessed in the Web via portals. Reusable components are needed to build such portals for different scientific disciplines and allowing uniform desktop access to remote resources. Such components will include tools and services enabling easy collaboration and job submission and job monitoring and component discovery and and persistent object storage. Based on experience gained from Grand Challenge applications for large-scale instruments and we demonstrate how Grid infrastructure components can be used to support the implementation of science portals. The availability of these components will simplify the prototype implementation of a common portal architecture.