I just recalled that not too long ago an ID proponent came here to question the inference of homology of relatively dissimilar protein sequences. The question appears to have been why anyone should believe that two non-identical proteins should be thought of as related (homologous - deriving from a common ancestor), and is there any reason to believe that you can sort of incrementally mutate two such proteins from a common ancestor while retaining it’s function as they become more and more dissimilar in sequence?
Take a look at table 2 in the paper. There’s a list of 250 different variants of DPBB-containing proteins, with internal sequence-identity ranging all the way from 45%(most similar known natural variants) to 4.5%(which remarkably is below the 5% similarity expected from randomly picking two sequences of similar length), at essentially every intermediate percentage spanning that “gap”. Those are extant proteins with internal sequence symmetry identities covering basically that entire range.
And now biochemists have shown that indeed the protein could have begun with a repeat of the exact same sequence, even using a plausible pre-biotic alphabet of just 7 amino acids.