Amino terminal and carboxyl terminal segments of actin participate in binding depactin an actin depolymerizing protein from starfish oocytes
Sutoh, K.; Mabuchi, I.
Biochemistry 23(26): 6757-6761
A one to one complex of actin monomer and depactin (an actin-depolymerizing protein isolated from starfish oocytes) was cross-linked with zero-length cross-linker 1-ethyl-3-[3'-(dimethylamino)propyl]carbodiimide (EDC) to generate a covalently cross-linked complex of actin and depactin. Cross-linking sites of depactin in the actin sequence were determined by mapping products after partial cleavages of the actin-depactin cross-linked complex. The peptide mappings revealed that acidic residues in the N-terminal segment of actin (Asp-1, Glu-2, Asp-3, Glu-4 and Asp-11) are candidates for one of the cross-linking sites of depactin while lysine and/or acidic residues in its C-terminal segment (Lys-358, Glu-360, Asp-362, Glu-363 and Lys-372) are candidates for another cross-linking site of depactin. Since EDC can cross-link amino and carboxyl groups only when they are in direct contact, it is very likely that some of those residues in the N-terminal and C-terminal segments of actin participate in binding depactin.