MF2130001 Archaeal histone hMfB 1bfm NMR Homodimer Methanothermus fervidus 8568866 Starich MR, Sandman K, Reeve JN, Summers MF J. Mol. Biol. 1996 1 255 187-203 The three-dimensional structure of the recombinant histone rHMfB from Methanothermus fervidus, an archaeon that grows optimally at 83 degrees C, has been determined by nuclear magnetic resonance methods. This is only the third structure of a protein from a hyperthermophilic organism (optimal growth at temperatures above 80 degrees C). Signal assignments were made using a combination of homonuclear-correlated, 15N-double resonance and 15N, 13C triple resonance NMR experiments. Long range dipolar interactions for the symmetric homodimer were identified from two-dimensional 13C-double half-filtered and three-dimensional 13C-filtered NMR data obtained for a heterolabeled-dimer. A family of 33 structures was calculated using DSPACE with a total of 609 NOE-derived interproton distance restraints, including 22 intraresidue, 192 sequential, 300 medium-range (two to five residues), 86 long-range intramolecular (more than five residues) and 112 intermolecular distance restraints. The monomer subunits consist of three alpha-helices, extending from residues Pro4 to Ala15 (helix I), Ser21 to Ala50 (helix II) and Lys56 to Lys68 (helix III), as well as two short segments of beta-strand comprised of residues Arg19 to Ser21 and Thr54 to Ile55. Helices I, II and III contain N-terminal capping boxes, and helices I and II contain C-terminal caps. The structure of the (rHMfB)2 dimer appears very similar to the dimer subunits within the histone core octamer of the chicken nucleosome. The presence of a canonical "histone fold" motif in rHMfB is consistent with the HMf family of archaeal histones and the eukaryal nucleosome core histones having evolved from a common ancestor. The (rHMfB)2 dimer contains several structural features that may impart thermal stability (or non-lability), including two novel hydrophobic "proline Ncaps", four interhelical hydrogen bonds and short N- and C-terminal disordered tails. GO:0003690 double-stranded DNA binding GO:0046982 protein heterodimerization activity GO:0042803 protein homodimerization activity GO:0005694 chromosome GO:0005737 cytoplasm GO:0006265 DNA topological change GO:0051260 protein homooligomerization 2 1 Histone-like interactions Histone-like complexes All chains according to the most probable oligomerization state stored in PDBe were considered. A DNA-binding protein HMf-2 Methanothermus fervidus P19267 1 69 100% MELPIAPIGRIIKDAGAERVSDDARITLAKILEEMGRDIASEAIKLARHAGRKTIKAEDIELAVRRFKK 69 secondary structure helix 4 16 secondary structure helix 21 51 secondary structure helix 56 68 secondary structure strand 19 20 pfam PF00808 Histone-like transcription factor (CBF/NF-Y) and archaeal histone 1 64 B DNA-binding protein HMf-2 Methanothermus fervidus P19267 1 69 100% MELPIAPIGRIIKDAGAERVSDDARITLAKILEEMGRDIASEAIKLARHAGRKTIKAEDIELAVRRFKK 69 secondary structure helix 4 16 secondary structure helix 21 51 secondary structure helix 56 68 secondary structure strand 54 55 pfam PF00808 Histone-like transcription factor (CBF/NF-Y) and archaeal histone 1 64 Direct evidence The full structure participates in mutual synergistic folding. Histone-like transcription factor (CBF/NF-Y) and archaeal histone Data on the GdmCl-induced unfolding and refolding transitions of the dimer (monitored by stopped-flow far UV CD) fitted to a two-state model (PMID:15313621). A N/A B N/A MF2130001 MF7000001 MF7000002 MF7000004 MF7000005 MF7000384 MF7000385