The kelch motif was initially discovered in Kelch (Swiss:Q04652). In this protein there are six copies of the motif. It has been shown that Swiss:Q04652 is related to Galactose Oxidase [1] for which a structure has been solved [2]. The kelch motif forms a beta sheet. Several of these sheets associate to form a beta propeller structure as found in Pfam:PF00064, Pfam:PF00400 and Pfam:PF00415.

1: Drosophila kelch motif is derived from a common enzyme fold. Bork P, Doolittle RF; J Mol Biol 1994;236:1277-1282. PMID:8126718

2: Novel thioether bond revealed by a 1.7 A crystal structure of galactose oxidase. Ito N, Phillips SE, Stevens C, Ogel ZB, McPherson MJ, Keen JN, Yadav KD, Knowles PF; Nature 1991;350:87-90. PMID:2002850

3: Crystal structure of the Kelch domain of human Keap1. Li X, Zhang D, Hannink M, Beamer LJ; J Biol Chem 2004;279:54750-54758. PMID:15475350