like most type ii restriction enzymes, "bgl"ii consists of two identical subunits that form a homodimer around the dna double helix. each monomer is 223 amino acids and symmetrically bind both sides of the unique palindromic nucleotide sequence agatct, cleaving the scissile phosphodiester bond between the first adenine and guanine nucleotides on both strands of the dna molecule, creating sticky ends with 5' end overhangs.