2rnz
Solution structure of the presumed chromodomain of the yeast histone acetyltransferase, Esa1
Structural highlights
FunctionESA1_YEAST Catalytic component of the NuA4 histone acetyltransferase (HAT) complex which is involved in epigenetic transcriptional activation of selected genes principally by acetylation of nucleosomal histones H4, H3, H2B, H2A and H2A variant H2A.Z. Acetylates histone H4 to form H4K5ac, H4K8ac, H4K12ac and H4K16ac, histone H3 to form H3K14ac, histone H2B to form H2BK16ac, histone H2A to form H2AK4ac and H2AK7ac, and histone variant H2A.Z to form H2A.ZK14ac. Acetylation of histone H4 is essential for DNA double-strand break repair through homologous recombination. Involved in cell cycle progression. Recruitment to promoters depends on H3K4me.[1] [2] [3] [4] [5] [6] [7] [8] [9] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedChromodomains are methylated histone binding modules that have been widely studied. Interestingly, some chromodomains are reported to bind to RNA and/or DNA, although the molecular basis of their RNA/DNA interactions has not been solved. Here we propose a novel binding mode for chromodomain-RNA interactions. Essential Sas-related acetyltransferase 1 (Esa1) contains a presumed chromodomain in addition to a histone acetyltransferase domain. We initially determined the solution structure of the Esa1 presumed chromodomain and showed it to consist of a well-folded structure containing a five-stranded beta-barrel similar to the tudor domain rather than the canonical chromodomain. Furthermore, the domain showed no RNA/DNA binding ability. Because the N-terminus of the protein forms a helical turn, we prepared an N-terminally extended construct, which we surprisingly found to bind to poly(U) and to be critical for in vivo function. This extended protein contains an additional beta-sheet that acts as a knot for the tudor domain and binds to oligo(U) and oligo(C) with greater affinity compared with other oligo-RNAs and DNAs examined thus far. The knot does not cause a global change in the core structure but induces a well-defined loop in the tudor domain itself, which is responsible for RNA binding. We made 47 point mutants in an esa1 mutant gene in yeast in which amino acids of the Esa1 knotted tudor domain were substituted to alanine residues and their functional abilities were examined. Interestingly, the knotted tudor domain mutations that were lethal to the yeast lost poly(U) binding ability. Amino acids that are related to RNA interaction sites, as revealed by both NMR and affinity binding experiments, are found to be important in vivo. These findings are the first demonstration of how the novel structure of the knotted tudor domain impacts on RNA binding and how this influences in vivo function. Novel structural and functional mode of a knot essential for RNA binding activity of the Esa1 presumed chromodomain.,Shimojo H, Sano N, Moriwaki Y, Okuda M, Horikoshi M, Nishimura Y J Mol Biol. 2008 May 16;378(5):987-1001. Epub 2008 Mar 19. PMID:18407291[10] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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