7vz2
From Proteopedia
Crystal structure of chromodomain of Arabidopsis LHP1
Structural highlights
FunctionLHP1_ARATH Structural component of heterochromatin involved in gene repression, including several floral homeotic genes and FLT that regulates flowering time. Required for maintenance of vernalization-induced repression of FLC. As part of the PRC1-like complex, recognizes and binds histone H3 tails methylated at 'Lys-9' (H3K9me) and 'Lys-27' (H3K27me), leading to epigenetic repression. PcG PRC1 complex maintains the transcriptionally repressive state of many genes, including Hox genes, throughout development. PcG PRC1 complex acts via chromatin remodeling and modification of histones, rendering chromatin heritably changed in its expressibility. Transcriptional repressor that binds DNA on GAGA-like motif and 5'-(A/G/T)AACCCTA(A/G)-3' consensus motif in the promoters of target genes. Recognizes and binds histone H3 tails methylated at 'Lys-27' (H3K27me) but depleted in active histone marks such as H3K4me, leading to epigenetic repression. When in complex with LHP1, recognizes and binds histone H3 tails methylated at 'Lys-4' (H3K4me) and 'Lys-27' (H3K27me), mostly corresponding to stress-responsive genes (PubMed:27495811).[1] [2] [3] [4] [5] [6] [7] Publication Abstract from PubMedArabidopsis LHP1 (LIKE HETEROCHROMATIN PROTEIN 1), a unique homolog of HP1 in Drosophila, plays important roles in plant development, growth, and architecture. In contrast to specific binding of the HP1 chromodomain to methylated H3K9 histone tails, the chromodomain of LHP1 has been shown to bind to both methylated H3K9 and H3K27 histone tails and LHP1 carries out its function mainly via its interaction with these two epigenetic marks. However, the molecular mechanism for the recognition of methylated histone H3K9/27 by the LHP1 chromodomain is still unknown. In this study, we characterized the binding ability of LHP1 to histone H3K9 and H3K27 peptides, and found that the chromodomain of LHP1 binds to histone H3K9me2/3 and H3K27me2/3 peptides with comparable affinities, while it exhibited no binding or weak binding to unmodified or mono-methylated H3K9/K27 peptides. Our crystal structures of the LHP1 chromodomain in peptide-free and peptide-bound forms coupled with mutagenesis studies reveal that the chromodomain of LHP1 bears a slightly different chromodomain architecture and recognizes methylated H3K9 and H3K27 peptides via a hydrophobic clasp, similar to the chromodomains of human Pc proteins, which could not be explained only based on primary structure analysis. Our binding and structural studies of the LHP1 chromodomain illuminate a conserved ligand interaction mode between chromodomains of both animals and plants, and shed light on further functional study of the LHP1 protein. Structural basis for the recognition of methylated histone H3 by the Arabidopsis LHP1 chromodomain.,Liu Y, Yang X, Zhou M, Yang Y, Li F, Yan X, Zhang M, Wei Z, Qin S, Min J J Biol Chem. 2022 Jan 21:101623. doi: 10.1016/j.jbc.2022.101623. PMID:35074427[8] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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