1qsr
CRYSTAL STRUCTURE OF TETRAHYMENA GCN5 WITH BOUND ACETYL-COENZYME A
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| , resolution 2.0Å | |||||||
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| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
OverviewOverview
Gene activation is a highly regulated process that requires the coordinated action of proteins to relieve chromatin repression and to promote transcriptional activation. Nuclear histone acetyltransferase (HAT) enzymes provide a mechanistic link between chromatin destabilization and gene activation by acetylating the epsilon-amino group of specific lysine residues within the aminoterminal tails of core histones to facilitate access to DNA by transcriptional activators. Here we report the high-resolution crystal structure of the HAT domain of Tetrahymena GCN5 (tGCN5) bound with both its physiologically relevant ligands, coenzyme A (CoA) and a histone H3 peptide, and the structures of nascent tGCN5 and a tGCN5/acetyl-CoA complex. Our structural data reveal histone-binding specificity for a random-coil structure containing a G-K-X-P recognition sequence, and show that CoA is essential for reorienting the enzyme for histone binding. Catalysis appears to involve water-mediated proton extraction from the substrate lysine by a glutamic acid general base and a backbone amide that stabilizes the transition-state reaction intermediate. Comparison with related N-acetyltransferases indicates a conserved structural framework for CoA binding and catalysis, and structural variability in regions associated with substrate-specific binding.
About this StructureAbout this Structure
1QSR is a Single protein structure of sequence from Tetrahymena thermophila. Full crystallographic information is available from OCA.
ReferenceReference
Structure of Tetrahymena GCN5 bound to coenzyme A and a histone H3 peptide., Rojas JR, Trievel RC, Zhou J, Mo Y, Li X, Berger SL, Allis CD, Marmorstein R, Nature. 1999 Sep 2;401(6748):93-8. PMID:10485713
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