1n6a
| |||||||
| , resolution 1.70Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | |||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
Structure of SET7/9
OverviewOverview
The methylation of lysine residues of histones plays a pivotal role in the regulation of chromatin structure and gene expression. Here, we report two crystal structures of SET7/9, a histone methyltransferase (HMTase) that transfers methyl groups to Lys4 of histone H3, in complex with S-adenosyl-L-methionine (AdoMet) determined at 1.7 and 2.3 A resolution. The structures reveal an active site consisting of: (i) a binding pocket between the SET domain and a c-SET helix where an AdoMet molecule in an unusual conformation binds; (ii) a narrow substrate-specific channel that only unmethylated lysine residues can access; and (iii) a catalytic tyrosine residue. The methyl group of AdoMet is directed to the narrow channel where a substrate lysine enters from the opposite side. We demonstrate that SET7/9 can transfer two but not three methyl groups to unmodified Lys4 of H3 without substrate dissociation. The unusual features of the SET domain-containing HMTase discriminate between the un- and methylated lysine substrate, and the methylation sites for the histone H3 tail.
About this StructureAbout this Structure
1N6A is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
ReferenceReference
Mechanism of histone lysine methyl transfer revealed by the structure of SET7/9-AdoMet., Kwon T, Chang JH, Kwak E, Lee CW, Joachimiak A, Kim YC, Lee J, Cho Y, EMBO J. 2003 Jan 15;22(2):292-303. PMID:12514135
Page seeded by OCA on Thu Mar 20 12:52:43 2008