1f1e
CRYSTAL STRUCTURE OF THE HISTONE FROM METHANOPYRUS KANDLERI
OverviewOverview
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).
About this StructureAbout this Structure
1F1E is a Single protein structure of sequence from Methanopyrus kandleri. Full crystallographic information is available from OCA.
ReferenceReference
An ancestral nuclear protein assembly: crystal structure of the Methanopyrus kandleri histone., Fahrner RL, Cascio D, Lake JA, Slesarev A, Protein Sci. 2001 Oct;10(10):2002-7. PMID:11567091 Page seeded by OCA on Fri May 2 15:46:36 2008