Domain families chromatin remodeling

Helicases catalyze the processive separation of duplex DNA into single strands. Despite sharing similarity to helicases, none of the chromatin remodelling factors, with the exception of the INO80 complex, have been shown to catalyze the separation of DNA strands (Shen et al, 2000). Instead, they can translocate on double-stranded (ds) DNA in an ATP-hydrolysis dependent manner and are characterized by their ability to generate superhelical torsional strain in DNA (Havas et al, 2000 Saha et al, 2002 Whitehouse et al, 2003). The crystal structure of Rad54, a member of the SWI/SNF family has been solved for both S. solfataricus and zebrafish which helps to understand the mechanism of the SWI/SNF ATPase domain in remodelling processes (Durr et al, 2005 Thoma et al, 2005). It reveals... 

Tsukada Y, Fang J, Erdjument-Bromage H, Warren ME, Borchers CH, Tempst P, Zhang Y (2006) Histone demethylation by a family of JmjC domain-containing proteins. Nature 439 811-816 van Holde K, Yager T (2003) Models for chromatin remodeling a critical comparison. Biochem Cell Biol 81 169-172... 

A large number of histone lysine methylation sites have been characterized, showing that the trimethylated state is prevalent. Given that LSDl demethylates only mono- and dimethylated lysine substrates, it seemed likely that additional enzymes would catalyze such a reaction. Indeed, the recent discovery of proteins that harbor a JmjC domain and have demethylase activity revealed a novel family of enzymes that also contain other domains associated with chromatin remodeling. 

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