IFT140 Contains 9 TPR repeats.Contains 5 WD repeats.WD-repeat-containing proteins are those that contain 4 or more copies of the WD-repeat, a sequence motif approximately 31 amino acids long, that encodes a structural repeat. This repeat is described by the following profile, where x is ANY amino acid. By clicking on each high-lighted character you will obtain the distribution of amino acids found at that position of the repeat among an aligned set of WD-repeat containing proteins. The tertiary structure of only one member of this family has been determined, that of the G protein beta subunit, which contains 7 WD-repeats. Each of the 7 repeats folds into a small antiparallel beta-sheet. The over-lines above indicate the position of these strands, with "a" being the strand closest to the central pore and "d" at the external surface of the folded protein.