Histone citrullination occurs by enzymatic conversion of arginine residue to citrulline. This leads to chromatin relaxation and enables activation of transcription.

What causes citrullination of proteins?

Citrullination or deimination is the conversion of the amino acid arginine in a protein into the amino acid citrulline. Citrulline is not one of the 20 standard amino acids encoded by DNA in the genetic code. Instead, it is the result of a post-translational modification.

Why does citrullination occur in rheumatoid arthritis?

1 The potential role of citrullination in RA pathogenesis arises from several observations: rheumatoid arthritis patients have an increase in citrullinated proteins and PAD activity in mucosal surfaces as well as in synovial fluid;2,3 the citrullination reaction relevant to RA is mediated by two isoforms, PAD 2 and 4, ...