5HT6 image
Entry Detail
PDB ID:
5HT6
Keywords:
Title:
Crystal structure of the SET domain of the human MLL5 methyltransferase
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2016-01-26
Release Date:
2016-11-16
Method Details:
Experimental Method:
Resolution:
2.09 Å
R-Value Free:
0.24
R-Value Work:
0.20
R-Value Observed:
0.21
Space Group:
P 31 2 1
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Histone-lysine N-methyltransferase 2E
Mutations:C453A
Chain IDs:A, B
Chain Length:138
Number of Molecules:2
Biological Source:Homo sapiens
Primary Citation
The Human Mixed Lineage Leukemia 5 (MLL5), a Sequentially and Structurally Divergent SET Domain-Containing Protein with No Intrinsic Catalytic Activity.
Plos One 11 e0165139 e0165139 (2016)
PMID: 27812132 DOI: 10.1371/journal.pone.0165139

Abstact

Mixed Lineage Leukemia 5 (MLL5) plays a key role in hematopoiesis, spermatogenesis and cell cycle progression. Chromatin binding is ensured by its plant homeodomain (PHD) through a direct interaction with the N-terminus of histone H3 (H3). In addition, MLL5 contains a Su(var)3-9, Enhancer of zeste, Trithorax (SET) domain, a protein module that usually displays histone lysine methyltransferase activity. We report here the crystal structure of the unliganded SET domain of human MLL5 at 2.1 Å resolution. Although it shows most of the canonical features of other SET domains, both the lack of key residues and the presence in the SET-I subdomain of an unusually large loop preclude the interaction of MLL5 SET with its cofactor and substrate. Accordingly, we show that MLL5 is devoid of any in vitro methyltransferase activity on full-length histones and histone H3 peptides. Hence, the three dimensional structure of MLL5 SET domain unveils the structural basis for its lack of methyltransferase activity and suggests a new regulatory mechanism.

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