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The crystal structure of MBTD1
Structural highlights
FunctionMBTD1_HUMAN Putative Polycomb group (PcG) protein. PcG proteins maintain the transcriptionally repressive state of genes, probably via a modification of chromatin, rendering it heritably changed in its expressibility (By similarity). Specifically binds to monomethylated and dimethylated 'Lys-20' on histone H4. 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 PubMedBACKGROUND: The Polycomb group (PcG) of proteins is a family of important developmental regulators. The respective members function as large protein complexes involved in establishment and maintenance of transcriptional repression of developmental control genes. MBTD1, Malignant Brain Tumor domain-containing protein 1, is one such PcG protein. MBTD1 contains four MBT repeats. METHODOLOGY/PRINCIPAL FINDINGS: We have determined the crystal structure of MBTD1 (residues 130-566aa covering the 4 MBT repeats) at 2.5 A resolution by X-ray crystallography. The crystal structure of MBTD1 reveals its similarity to another four-MBT-repeat protein L3MBTL2, which binds lower methylated lysine histones. Fluorescence polarization experiments confirmed that MBTD1 preferentially binds mono- and di-methyllysine histone peptides, like L3MBTL1 and L3MBTL2. All known MBT-peptide complex structures characterized to date do not exhibit strong histone peptide sequence selectivity, and use a "cavity insertion recognition mode" to recognize the methylated lysine with the deeply buried methyl-lysine forming extensive interactions with the protein while the peptide residues flanking methyl-lysine forming very few contacts [1]. Nevertheless, our mutagenesis data based on L3MBTL1 suggested that the histone peptides could not bind to MBT repeats in any orientation. CONCLUSIONS: The four MBT repeats in MBTD1 exhibits an asymmetric rhomboid architecture. Like other MBT repeat proteins characterized so far, MBTD1 binds mono- or dimethylated lysine histones through one of its four MBT repeats utilizing a semi-aromatic cage. ENHANCED VERSION: This article can also be viewed as an enhanced version in which the text of the article is integrated with interactive 3D representations and animated transitions. Please note that a web plugin is required to access this enhanced functionality. Instructions for the installation and use of the web plugin are available in Text S1. Structural studies of a four-MBT repeat protein MBTD1.,Eryilmaz J, Pan P, Amaya MF, Allali-Hassani A, Dong A, Adams-Cioaba MA, Mackenzie F, Vedadi M, Min J PLoS One. 2009 Oct 20;4(10):e7274. PMID:19841675[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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