Note the blue atoms (Nitrogen) at the peptide bonds and in the guanidyl group of arginine. The red denotes oxygen atoms and carbon atoms are marked grey. Hydrogen atoms are not indicated. The relative hydrophobicity of the Adda moiety is depicted here, as is the potential binding capacity of the central core for metal ions. The amino acid methyldehydroalanine forms a covalent bond with a cys residue of protein phosphatases (PPases) in disrupting PPase activity, causing toxicity.