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. Author manuscript; available in PMC: 2015 Dec 23.
Published in final edited form as: Mol Cell. 2007 Nov 30;28(4):677–691. doi: 10.1016/j.molcel.2007.10.023

Figure 1. Structural and Functional Characterization of L3MBTL1 as a Lower Lysine Methylation State-Specific Effector Module.

Figure 1

(A) Domain architecture of the L3MBTL1197–526 used for structural and functional study in this figure.

(B) (Left panel) Fluorescence polarization titration curves for wild-type L3MBTL1197–526 with H31–15 peptides containing either unmodified (blue) or mono- (red), di- (green), and tri- (purple) methyllysine at position 9. (Right panel) Fluorescence polarization titration curves for H31–15K9me1 peptide binding to L3MBTL1197–526 proteins containing Asp to Asn mutants in each of the three binding pockets. The binding curves are black for wild-type L3MBTL1, orange for pocket 1 D248N mutant, red for pocket 2 D355N mutant, and cyan for pocket 3 D459N mutant. The apparent dissociation constants (KD) are listed in each panel. In each case, parameters are reported as the mean (±average deviation from the mean) obtained from three independent titration experiments.

(C) Surface representation of crystal structure of L3MBTL1197–526-H1.523–27K27me2 complex with “PS”-containing C-terminal tail of a symmetry-related L3MBTL1 molecule in pocket 1, K27me2 in pocket 2, and PEG ligand in pocket 3. The red to blue coloring encodes an electrostatic potential distribution ranging from −20 to 20 kT/e on the protein surface.

(D to F) Structural details of Pro insertion of PS peptide into pocket 1 (D), K27me2 insertion into pocket 2 (E), and PEG ligand insertion into one of the entrances to pocket 3 (F).The aromatic residues of each pocket are highlighted in the “dotted” van der Waals radius representation. The hydrogen bonds involving the Asp residue lining the aromatic cage are shown as red dashes, with bond length listed nearby.