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| {{STRUCTURE_1qst| PDB=1qst | SCENE= }} | | {{STRUCTURE_1qst| PDB=1qst | SCENE= }} |
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| '''CRYSTAL STRUCTURE OF TETRAHYMENA GCN5'''
| | ===CRYSTAL STRUCTURE OF TETRAHYMENA GCN5=== |
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| ==Overview==
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| 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.
| | The line below this paragraph, {{ABSTRACT_PUBMED_10485713}}, adds the Publication Abstract to the page |
| | (as it appears on PubMed at http://www.pubmed.gov), where 10485713 is the PubMed ID number. |
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| | {{ABSTRACT_PUBMED_10485713}} |
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| ==About this Structure== | | ==About this Structure== |
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| [[Category: Gcn5-related n-acetyltransferase]] | | [[Category: Gcn5-related n-acetyltransferase]] |
| [[Category: Histone acetyltransferase]] | | [[Category: Histone acetyltransferase]] |
| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 06:39:59 2008'' | | |
| | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jul 28 22:52:37 2008'' |
