I don't know that I agree that fragment libraries use sequence homology. From my understanding of it, homology implies an actual evolutionary relationship. Wh

I don't know that I agree that fragment libraries use sequence homology. From my understanding of it, homology implies an actual evolutionary relationship. Wheras fragment libraries instead are agnostic and instead seem to be based on the idea that short fragments of non-related proteins can match up in sequence and structure space. Nobody looks at 3-mers and 9-mers in homology modelling; it's typically well over 25 amino acids long, and there is usually a plausible whole-domain (in the SCOP terminology). But, the protein field has always played loose with the term "homology".