Structural variations in actins. Biochemical and immunological tools for probing the structure of rabbit skeletal-muscle and bovine aortic actins.

Structural differences between skeletal-muscle and aortic actins were studied by using biochemical and immunological approaches. By using proteinase digestion we found that three regions of actin show structural differences: (a) in the C-terminal part, (b) the region around residue 227 and (c) the region around residue 167. By using antibodies specific to particular actin conformations we can discriminate between monomeric and filamentous forms of the two actins. Our results show that the minor sequence variations of the N- and C-terminal regions induce structural change in these regions, but also some long-range structural variations in other regions.