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PDBsum entry 5bjs
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References listed in PDB file
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Key reference
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Title
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Polycomb repressive complex 2 in an autoinhibited state.
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Authors
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M.Bratkowski,
X.Yang,
X.Liu.
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Ref.
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J Biol Chem, 2017,
292,
13323-13332.
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PubMed id
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Abstract
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Polycomb-group proteins control many fundamental biological processes, such as
anatomical development in mammals and vernalization in plants. Polycomb
repressive complex 2 (PRC2) is responsible for methylation of histone H3 lysine
27 (H3K27), and trimethylated H3K27 (H3K27me3) is implicated in epigenetic gene
silencing. Recent genomic, biochemical, and structural data indicate that PRC2
is broadly conserved from yeast to human in many aspects. Here, we determined
the crystal structure of an apo-PRC2 from the fungusChaetomium
thermophilumcaptured in abona fideautoinhibited state, which
represents a novel conformation of PRC2 associated with enzyme regulation in
light of the basal and stimulated states that we reported previously. We found
that binding by the cofactorS-adenosylmethionine mitigates this
autoinhibited structural state. Using steady-state enzyme kinetics, we also
demonstrated that disrupting the autoinhibition results in a vastly activated
enzyme complex. Autoinhibition provides a novel structural platform that may
enable control of PRC2 activity in response to diverse transcriptional states
and chromatin contexts and set a ground state to allow PRC2 activation by other
cellular mechanisms as well.
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