Abstract: The invention provides a series of GMPS enzyme inhibitors. The invention includes potent GMPS inhibitors that specifically and covalently bind to GMPS, exhibit broad anti-cancer activity, block the infection efficiency of viruses, and have the potentials to suppress undesired immune responses. These novel inhibitors of GMPS, and their derivatives, have tremendous potentials to be used as therapeutic agents for the treatment of cancers, viral infection and immune disorders.

Abstract: The present invention relates to a method of forming a macrocyclic peptide bearing a pharmacophore and said produced macrocyclic peptide, wherein the method comprises the steps of: reacting a peptide with two thiol groups of cysteine side chains with the reactive compound 1,5-dichloropentanedion-2,4. The reaction between the reactive compound and the peptide produces an 1,3-diketone-containing macrocyclic polypeptide. The macrocycle with a 1,3-diketone group is then modified by reaction of said macrocycle with an alkyl or aryl hydrazine group bearing a pharmacophore in benign aqueous conditions. The macrocycles may be displayed in a library, such as a phage display library, and used to biopan for affinity against a selected target.