Histone and DNA binding ability studies of the NSD subfamily of PWWP domains.

The NSD proteins, namely NSD1, NSD2 and NSD3, are lysine methyltransferases, which catalyze mono- and di-methylation of histone H3K36. They are multi-domain proteins, including two PWWP domains (PWWP1 and PWWP2) separated by some other domains. These proteins act as potent oncoproteins and are implicated in various cancers. However the biological functions of these PWWP domains are still largely unknown. To better understand the functions of these proteins' PWWP domains, we cloned, expressed and purified all the PWWP domains of these NSD proteins to characterize their interactions with methylated histone peptides and dsDNA by quantitative binding assays and crystallographic analysis. Our studies indicate that all these PWWP domains except NSD1_PWWP1 bind to trimethylated H3K36, H3K79 peptides and dsDNA weakly. Our crystal structures uncover that the NDS3_PWWP2 and NSD2_PWWP1 domains, which hold an extremely long α-helix and α-helix bundle, respectively, need a conformation adjustment to interact with nucleosome. • NSD PWWP domains except NSD1_PWWP1 bind to histone H3K36/79me3 and dsDNA weakly. • The NSD3_PWWP2 holds a unique long C-terminal α-helix following the β-barrel. • The NSD2_PWWP1 bears a C-terminal α-helix bundle containing 4 α-helices. • NSD PWWPs interact with methylated histone similar to other reported PWWP domains. • NSD3_PWWP2 and NSD2_PWWP1 need conformational changes to interact with nucleosome. [ABSTRACT FROM AUTHOR]