Amine-to-amine crosslinkers are a good choice for your application since amino groups are usually abundant on the surface of proteins. Our most popular amine-reactive homobifunctional crosslinker that is water-soluble is BS3 (Cat. No. A39266). This has a moderate-length (11.4 A) linker that is good for linking adjacent proteins. If you need the ability to cleave the linker with sulfhydryl reducing agents I would suggest DTSSP (Cat. No. 21578). If you think you might need an extra-long crosslinker, then BS(PEG)5 (Cat. No. 21581) or BS(PEG)9 (Cat. No. 21582) are alternatives.
Find additional tips, troubleshooting help, and resources within our Protein Purification and Isolation Support Center.