Comment | Hercynine is the betaine (trimethylated amino group) form of histidine. This protein occurs in a conserved four-gene cyanobacterial cassette along with a EgtD, the methyltransferase that converts histidine to hercynine as in ergothioneine biosynthesis, an EgtB homolog that is likely to attach some thiol (e.g. gamma-glutamyl-cysteine) through its sulfur to the hercynine imidazole ring, and a small protein of unknown function (TIGR04374). Members are distantly related to phage shock protein A (PspA). |