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

Uversky, Vladimir N

Phytochelatins. Heavy metal detoxification in higher plants is dependent on a set of heavy-metal-complexing peptides, phytochelatins, with structure of (γ-glutamic acid-cysteine) n -glycine (n = 2-11) [(γ-Glu-Cys) n -Gly]. 183 The longest of these peptides possesses a molecular mass of 2.6 kDa, a pI 3.26 and a net charge of −11. These peptides are induced by the exposure of plants to ARGLU1. Transcriptional activators and RNA polymerase II are bridged via the central transcriptional coactivator complex, the Mediator complex. It has been recently shown that the arginine and glutamate rich 1 protein (ARGLU1) colocalizes with the Mediator subunit 1 (MED1) in the nucleus, being in contact with the far C-terminal region of MED1. 190 This ARGLU1-MED1 interaction is crucial for the estrogen-dependent gene transcription and breast cancer cell growth. 190 Human ARGLU1 is a 270 residues-long protein that contains 53 arginines and 54 glutamates. There are two regions with significant composition biases in this protein, an arginine-rich region (residues 3-74) that contains 25 arginines and a glutamic acid-rich region (residues 27-251) containing 49 glutamic acids.