Abstract: The present invention is to construct a DNA replication reaction system which is excellent in versatility and is easily used. An amino acid sequence of a PCNA monomer which is one of factors involved in DNA replication is prepared so that amino acid residues causing mutual charge repulsion constitute a site which causes, when an N terminal region of the PCNA monomer and a C terminal region of another PCNA monomer act as an interface to form a multimeric complex, an intermolecular interaction of the monomers in an interface region of the monomers.

Abstract: The present invention is to construct a DNA replication reaction system which is excellent in versatility and is easily used. An amino acid sequence of a PCNA monomer which is one of factors involved in DNA replication is prepared so that amino acid residues causing mutual charge repulsion constitute a site which causes, when an N terminal region of the PCNA monomer and a C terminal region of another PCNA monomer act as an interface to form a multimeric complex, an intermolecular interaction of the monomers in an interface region of the monomers.

Abstract: The task is to provide protein interaction inhibitors and/or detection method for interaction inhibitors related to regulation of T cell activation and production of IL-2. The present invention provides inhibitors of interaction between PKC theta and KPNA1, and inhibitors of interaction between KPNA1 and NF-kappaB. Inhibitors of interaction is defined as an candidate compound demonstrating the inhibition of interaction by assaying whether interaction has occurred or not between 2 types of protein and the candidate compound under the conditions allowing interaction of each combination. The detection kit is equipped with samples providing proteins of combinations to be interacted.