Lysyl oxidase‐like 2 (LOXL2) oxidizes trimethylated lysine 4 in histone H3

Methylation of histone H3 lysine 4 is linked to active transcription and can be removed by LSD1 or the JmjC domain‐containing proteins by amino‐oxidation or hydroxylation, respectively. Here we describe that its deamination can be catalyzed by lysyl oxidase‐like 2 protein (LOXL2), presenting an unconventional chemical mechanism for H3K4 modification. Infrared spectroscopy and mass spectrometry analyses demonstrated that recombinant LOXL2 specifically deaminates trimethylated H3K4. Moreover, by regulating H3K4me3 deamination, LOXL2 activity is linked with the transcriptional control of the CDH1 gene. These results reveal the existence of further H3 modification as well as a novel mechanism for H3K4me3 demethylation. Database The GEO accession number for the data referred to this paper is GSE35600. Herranz et al. show that trimethylated lysine 4 in histone H3 can be deaminated by LOXL2 revealing the existence of a new modification of H3 as well as a novel mechanism for H3K4me3 demethylation. Moreover, the authors demonstrate how this oxidation of H3 is linked with transcriptional repression of the CDH1 gene.