I'd start by pulling back a bit, and, rather than focusing on proteins, focus on the idea of microorganisms adapting to different environment. You might look at the ideas of "panspermia," which discuss how spores or microscopic organisms might have brought life to Earth by traveling through space. Likewise, you might look up "astrobiology," which is the more formal study of such issues. Both searches will help you discuss how the Andromeda strain might or might not adapt to our environment.