first malignant brain tumor (MBT) repeat found in Lethal(3)malignant brain tumor-like protein 1 (L3MBTL1)
L3MBTL1, also called L(3)mbt-like, or L(3)mbt protein homolog, is a Polycomb group (PcG) protein that functions as a 'reader' of a network of post-translational modifications by specifically recognizing and binding mono- and dimethyllysine residues on target proteins. It acts as a chromatin compaction factor by binding mono- and dimethylated histone H1b/HIST1H1E at 'Lys-26' (H1bK26me1 and H1bK26me2) and histone H4 at 'Lys-20' (H4K20me1 and H4K20me2), leading to condensed chromatin and repressed transcription. L3MBTL1 contains three MBT (malignant brain tumor) repeats. The MBT repeat is a protein module that recognizes methylated lysine residues on histones. MBT repeats contain a semi-aromatic cage to accommodate methyllysine and show specificity towards the lower methylation states of lysine. This model corresponds to the first MBT repeat that contains the semi-aromatic cage and may bind methylated lysine residues.
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