Simplified method for recombinant linker histone H1 purification.

We report a simplified alternative protocol for purification of recombinant linker histone H1 under non-denaturing conditions. This method takes advantage of the strong affinity of H1 to DNA and comprises nucleoprotein complex extraction from the lysate of bacterial cells overexpressing the protein, followed by two ion-exchange purification steps. The purity of the protein was at least 95%; the purified H1 was tested for nucleosome binding and was successfully fluorescently labeled for further studies.