The amino acid sequences of the human skeltal muscle actin and the Tetrahymena thermophila macronuclear actin were annlyzed and compared to the actin three-dimensional domain structure.
The variation analysis of 96 actin sequences showed that five out of the six loop regions connecting the subdomains were conservative and one loop region was variavle.
These results suggest the usefulness of the amino acid sequence analysis methods to get information about the domain structure of a conservative protein.