The invention discloses the use of an artificial protein for isolating a nucleosome, the nucleosome comprising a multiple-modified histone protein octamer, wherein the artificial protein comprises a first histone modification binding domain of 50 to 200 amino acids binding to a first histone modification, a second histone modification binding domain of 50 to 200 amino acids binding to a second histone modification, a linker of 5 to 50 amino acids connecting the first and the second histone modification binding domain, and an affinity tag. Further disclosed are a nucleic acid encoding the artificial protein, a host cell comprising the nucleic acid and a kit for isolating a nucleosome, the nucleosome comprising a multiple-modified histone protein octamer. Further disclosed is an in-vitro method for isolating a nucleosome having a first and a second histone modification.