1N3J: Structure and Substrate of a Histone H3 Lysine Methyltransferase from Paramecium Bursaria Chlorella Virus 1

Site-specific lysine methylation of histones by SET domains is a hallmark for epigenetic control of gene transcription in eukaryotic organisms. Here we report that a SET domain protein from Paramecium bursaria chlorella virus can specifically di-methylate Lys27 in histone H3, a modification implicated in gene silencing. The solution structure of the viral SET domain reveals a butterfly-shaped head-to-head symmetric dimer different from other known protein methyltransferases. Each subunit consists of a Greek-key antiparallel beta-barrel and a three-stranded open-faced sandwich that mediates the dimer interface. Cofactor S-adenosyl-L-methionine (SAM) binds at the opening of the beta-barrel, and amino acids C-terminal to Lys27 in H3 and in the flexible C-terminal tail of the enzyme confer the specificity of this viral histone methyltransferase.
PDB ID: 1N3JDownload
MMDB ID: 21818
PDB Deposition Date: 2002/10/28
Updated in MMDB: 2007/11
Experimental Method:
solution nmr
Source Organism:
Similar Structures:
Molecular Components in 1N3J
Label Count Molecule
Proteins (2 molecules)
Histone H3 Lysine Methyltransferase
Molecule annotation
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Citing MMDB