Crystallization and preliminary X-ray characterization of the Methanothermus fervidus histones HMfA and HMfB.

HMfA and HMfB are histone proteins from the thermophilic archaeon Methanothermus fervidus. They wrap DNA into nucleosome-like structures and appear to represent the basic core histone fold. HMfA was crystallized in space groups P4(2)2(1)2 and P2(1)2(1)2(1). HMfB crystallized in space group P2(1)2(1)2, while a selenomethionine-substituted variant, SeMet-HMfB, yielded crystals in C222(1). In all crystal forms HMfA, HMfB, or SeMet-HMfB may be present as homodimers.