Why some proteins (or parts of proteins) are intrinsically disordered?

They Contain protein segments that Disordered regions less-defined structure. (Lys, Arg, Glu, and Pro). -they can conform to many different proteins, facilitating interaction with numerous different partner proteins. -They lack a hydrophobic core, and instead are characterized by high densities of charged amino acid residues, -Structural disorder and high charge density can facilitate the function of some proteins.