Relationships of consensus kelch-motifs to propeller blade structure. A, Side view of single propeller blade structure from galactose oxidase (1GOF). β-strands are color-coded as in Fig. 1A and the nomenclature for the intra- and inter-blade loops is indicated. B, Alignment of consensus kelch motifs derived from BTB/kelch subgroups 1 and 2A to blade structure, demonstrating distinctions in the 2–3 loop size and charge distribution. The position of each β-strand is indicated.