NCIt definition : WD40 Repeats are found in signal transduction, mRNA processing, cytoskeletal assembly,
and cell cycle proteins; none are catalytic. G-beta is the prototypic WD40 protein.
WD-40 proteins contain 5-8 repeats of about 40 residues, with a central Trp-Asp (WD)
motif. The repeats may span the entire protein or make up either terminal or the central
section. WD40 domains serve as a platform to which proteins stably or reversibly bind;
some may recognize phosphoSer and -Thr peptides. The repeat forms a closed ring propeller
with seven blades each composed of a four-stranded anti-parallel b-sheet. Each repeat
forms the first three strands of one blade and the last strand in the next blade.
The last C-terminal repeat completes the blade of the first repeat. Residues on the
propeller top surface likely coordinate interactions with other proteins or ligands.;