Is there a database for immunoglobulin domain structure?
There are a number of databases that exist, though the one you would want to use will likely depend on what you need it for. The one that's recommended at my university is IgBlast, associated with The National Center for Biotechnology Information (NCBI), however I've seen IMGT as a recommended source, as well; it seems to have a wider array of tools. That being said, I can't say which you might find more beneficial, as I'm uncertain as to how you'd be using the resource.