Fig. 1.
(A) Domain organization of the full-length Drosophila Spire and representation of the constructs used in this work. The WH2 domains are shown in yellow. KIND, the kinase noncatalytic C-lobe domain; mFYVE, a modified zinc finger motif found in four cysteine-rich proteins; JNKB, the c-Jun N-terminal kinase binding domain (16). (B–D) Comparison of the structures of WH2 domains of SpirD, SpirABCD, SpirBCD, SpirCD, and SpirDDD. Electron densities (omit maps) are colored green; the polyglycine model, represented as sticks, is in red; actins are shown as gray surface plots; conserved residues are marked with arrows. The side chains of SpirD and SpirDDD are visible and have well-defined electron densities. In the case of the averaged WH2 domains, conserved residues were recognizable because of an elongated electron density; however, the averaging precluded the assignment of these residues to specific WH2 domain. (B) The WH2 domain of SpirD. (C) The averaged WH2 domain of SpirABCD, SpirBCD, and SpirCD. (D) The WH2-D domain of SpirDDD.