Histone H3 Citrullinated/H3Cit [MD323R]

Histone H3 is one of the five main histone proteins involved in the structure of chromatin in eukaryotic cells. Featuring a main globular domain and a long N-terminal tail, H3 is involved with the structure of the nucleosomes of the ‘beads on a string’ structure. Histone posttranslational modifications, such as methylation, acetylation, ubiquitination and citrullination can have profound effects on their structure and function and have been linked to various diseases. Citrullinated histone H3 (H3Cit) is the product of the posttranslational conversion of peptidyl arginine to citrulline on the N-terminal of histone H3. The subsequent decrease in positive charge of the histone residue results in a weaker binding to the negatively charged DNA, leading to chromatin decondensation. Histone citrullination is catalyzed by the enzyme peptidylarginine deiminase 4 (PAD4). H3Cit is a central marker of neutrophil extracellular traps (NETs) that acts as an autoantigen to induce the production of anti-citrullinated protein antibodies associated with various diseases such as sepsis, multiple sclerosis, rheumatoid arthritis and lupus. Histone hypercitrullination via PAD4 may also play a role in the progression of various cancers including multiple myeloma, acute myeloid leukemia, lung cancer, and hepatocellular carcinoma. H3Cit is a potential diagnostic and prognostic blood marker associated with an exacerbated inflammatory response in patients with advanced cancer. This antibody recognizes histone H3 citrullinated at residue Arg17, and perhaps residue Arg26, but does not cross-react with any other known citrullinated or methylated arginine residues on histone H3.