1qsn
From Proteopedia
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CRYSTAL STRUCTURE OF TETRAHYMENA GCN5 WITH BOUND COENZYME A AND HISTONE H3 PEPTIDE
Overview
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 Structure
1QSN is a Protein complex structure of sequences from Saccharomyces cerevisiae and Tetrahymena thermophila with COA as ligand. Full crystallographic information is available from OCA.
Reference
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
Page seeded by OCA on Wed Nov 21 00:56:56 2007
