Final answer:
Proteins of similar function might not be homologous due to convergent evolution. While they can have similar functional structures, their amino acid sequences and finer structural details will likely differ due to distinct evolutionary paths.
Step-by-step explanation:
Under circumstances of convergent evolution, one might expect proteins of similar function to not share homology. Convergent evolution occurs when different organisms independently evolve similar traits or functions, often in response to similar environmental challenges or ecological niches, despite not having a common ancestor. This means that proteins from different evolutionary lineages could end up performing similar functions but without having a shared evolutionary history, which is what homology represents.
As for the prediction about the structural similarity of such proteins, it is possible that they could have similar three-dimensional shapes, despite having different amino acid sequences. This is due to the fact that certain protein structures are particularly conducive to specific functions. However, due to the lack of a shared evolutionary history, the specific amino acid sequences and the finer details of the protein structures are likely to be different.