Compare protein functionality between species

Question

[Howard]

I'm doing a project where I compare amino acid sequences for a specific protein between multiple species. I know they have the gene and that they produce the protein; what I am trying to ascertain is how they differ in their functionality. How do the differences in the amino acid sequences affect the functionality of the protein they encode? After aligning both the exon and amino acid sequences I can safely say that the protein is highly conserved as it is virtually identical in all species, though there are a few places where two consecutive amino acids differ, and one where it is four amino acids. Has anyone ever tried to infer the functionality of the protein based on the amino acid sequence?

Answer 1

[Mensur Dlakic]

It is difficult to put an exact number to it, but let's say that proteins of similar length and >70-80% identity at amino-acid level are pretty much guaranteed to have identical functionality. The same is known to be true even for much lower degree of sequence identity, but it is less of a sure thing.