Histone arginine demethylase

Neither structure provides a direct view on the catalytic mechanism of these enzymes. However, prior biochemical and structural studies on bacterial MTases in complex with DNA revealed a mechanism involving base-flipping followed by a nudeophilic attack of a conserved cysteine on carbon C6 of the cytosine to be 

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T. (2004) Histone deimination antagonizes arginine methylation. Cell, 118, 545—553. 71 Chang, B., Chen, Y, Zhao, Y. and Bruick, R.K. (2007) JMJD6 is a histone arginine demethylase. Science, 318, 444-447. 

Histone deacetylases (HDACs), histone acetyltransferases (HMTs), histone demethylases (HDMTs), protein arginine methyltransterases (PRMTs), histone arginine demethylases (HADs), and DNA methyltransferases (DNMTs). 

Of special interest is the finding of the first histone arginine demethylase, the Jumonji domain-containing 6 protein (JMJD6). 

It shares homology with the JmjC domains found in the histone lysine demethylases. JMJD6 can demethylate H3 R2 and H4 R3 in biochemical and cell-based assays (42). The recent data that are emerging place histone arginine methylation as a key player of cell growth and cell proliferation processes. 

Histone methylation is a common posttranslational modification fond in histones. Histone methylations have been identified on lysine and arginine residues. In case of lysines S-adenosyl-methionine (SAM) dependent methyl transferases catalyze the transfer of one, two or three methyl groups. Lysine methylation is reversible and lysine specific demethylases have been... 

Reversible histone methylation is a highly specific process that is catalyzed by the action of histone methyltransferases (HMTs) and histone demethylases on lysine and arginine residues. Like DNMTs, HMTs employ a SAM cofactor. Lysine can be... 

Figure 13.2 (a) Sequential methylation and demethylation of lysines catalyzed by histone methyl transferases (HMTs) and histone demethylases (HDMs), respectively, (b) Sequential methylation and demethylation of arginines catalyzed by HMTs and HDMs, respectively, leading to symmetric and asymmetric dimethylarginines. 

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