1F1E: Crystal Structure Of The Histone From Methanopyrus Kandleri

Eukaryotic histone proteins condense DNA into compact structures called nucleosomes. Nucleosomes were viewed as a distinguishing feature of eukaryotes prior to identification of histone orthologs in methanogens. Although evolutionarily distinct from methanogens, the methane-producing hyperthermophile Methanopyrus kandleri produces a novel, 154-residue histone (HMk). Amino acid sequence comparisons show that HMk differs from both methanogenic and eukaryotic histones, in that it contains two histone-fold ms within a single chain. The two HMk histone-fold ms, N and C terminal, are 28% identical in amino acid sequence to each other and approximately 21% identical in amino acid sequence to other histone proteins. Here we present the 1.37-A-resolution crystal structure of HMk and report that the HMk monomer structure is homologous to the eukaryotic histone heterodimers. In the crystal, HMk forms a dimer homologous to [H3-H4](2) in the eukaryotic nucleosome. Based on the spatial similarities to structural ms found in the eukaryotic nucleosome that are important for DNA-binding, we infer that the Methanopyrus histone binds DNA in a manner similar to the eukaryotic histone tetramer [H3-H4](2).
PDB ID: 1F1EDownload
MMDB ID: 17618
PDB Deposition Date: 2000/5/18
Updated in MMDB: 2001/11
Experimental Method:
x-ray diffraction
Resolution: 1.37  Å
Source Organism:
Similar Structures:
Biological Unit for 1F1E: dimeric; determined by author and by software (PISA,PQS)
Molecular Components in 1F1E
Label Count Molecule
Proteins (2 molecules)
Histone Fold Protein
Molecule annotation
Chemicals (2 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB