1n3j: Difference between revisions

[[Image:1n3j.jpg|left|200px]]

'''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.

1N3J is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Paramecium_bursaria_chlorella_virus_1 Paramecium bursaria chlorella virus 1]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1N3J OCA].  

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