The alphabet of intrinsic disorder: II. Various roles of glutamic acid in ordered and intrinsically disordered proteins

Uversky, Vladimir N

There are also several other GARPs in various organisms, the functions of which are not known as of yet. Small GARP (a 112-amino acid protein, with a molecular mass of 13.1 kDa and an isoelectric point of 3.94, 29 residues of which are glutamic acids) was found in Euplotes octocarinatus. 214 Plasmodium falciparum GARP consists of 679 residues, 169 of which are glutamic acids. 215 Rhox8/Tox. Reproductive homeobox 8 protein (Rhox8 or Tox) is a homeodomain protein which is distantly related to the members of the Paired/Pax family belonging to the PEPP subfamily of Paired-like homeobox proteins. 216 In mice, Tox is predominately transcribed in the testis and ovary and potentially plays an important role during gametogenesis. 216 This 320 residues-long protein contains 113 glutamic acids organized in two poly-glutamic acid stretches (residues 111-139 and 177-201) and several Glu-rich regions, which together with 11 aspartic acids makes Rhox8 highly acidic (pI 3.95).