PMID: 27697561

Authors:

Gatchalian J, Ali M, Andrews FH, Zhang Y, Barrett AS, Kutateladze TG

Title:

Structural Insight into Recognition of Methylated Histone H3K4 by Set3.

Journal:

J Mol Biol. 2016 Sep 30. pii: S0022-2836(16)30400-4. doi:, 10.1016/j.jmb.2016.09.020.

Abstract:

The plant homeodomain (PHD) finger of Set3 binds methylated lysine 4 of histone H3 in vitro and in vivo; however, precise selectivity of this domain has not been fully characterized. Here, we explore the determinants of methyllysine recognition by the PHD fingers of Set3 and its orthologs. We use X-ray crystallographic and spectroscopic approaches to show that the Set3 PHD finger binds di- and trimethylated states of H3K4 with comparable affinities and employs similar molecular mechanisms to form complexes with either mark. Composition of the methyllysine-binding pocket plays an essential role in determining the selectivity of the PHD fingers. The finding that the histone-binding activity is not conserved in the PHD finger of Set4 suggests different functions for the Set3 and Set4 paralogs.