Figure 1
Sequence alignment of the N-terminal region of Expansion and Smad MH2 domains. (a) Sequence alignment of the N-terminal region of the D. melanogaster Expansion protein with orthologous proteins found in the Hexapoda, Arthopoda and Nematoda phyla. These sequences were obtained using BLAST. Using a PSI-BLAST search, we also detected sequence similarity to the MH2 domain of Smads. The Homo sapiens and Drosophila Smad2 MH2 domains are included in the alignment for comparison. Additional entries corresponding to uncharacterized proteins were not included in the alignment. A sequence alignment of the full-length proteins belonging to the Expansion family and a list of the entries included in the alignment are given as Supporting Information. The elements of secondary structure corresponding to the Expansion Nα-MH2 domain are highlighted at the top of the alignment, with the elements of secondary structure labelled. The results of the secondary-structure prediction used to guide us in the definition of the protein boundaries are shown below. For comparison, the secondary-structure elements corresponding to the human Smad2 domain are depicted below the alignment. (b) Schematic representation of the domain organization in Smad proteins and Expansion, indicating the boundaries of the prepared Nα-MH2 constructs. |