ATP ATP PDB 2BTE G-actin PDB 2BTF G-actin Actin monomer, depicted above in two display modes, has subdomains 1-4 ATP A simplified cartoon is at right ATP binds, along with Mg+t, within a deep cleft between subdomains 2&4 Actin monomer with boundActin monomer, depicted above in two display modes, has subdomains 1-4. A simplified cartoon is at right. ATP binds, along with Mg++, within a deep cleft between subdomains 2 & 4. Actin monomer with bound ATP PDB 2BTF G-actin ATP PDB 2BTF G-actin ATP 1 2 3 4