Fig. 1

Secondary structural elements and SNARE-binding residues of giardial SNAPs. a Sequence alignment of the putative giardial SNAPs with Sec17 of S. cerevisiae. α-helical regions of the Sec17 crystal structure (1QQE) have been marked with white boxes below the sequence alignment. The regions of the Giardia SNAPs that are predicted to be α-helical have been marked with colored boxes (SNAP₁₇₂₂₄, cherry; SNAP₁₆₅₂₁, fawn; SNAP₁₀₈₅₆, green) above the alignment. Lines indicate loops regions and dashed lines denote the disordered regions in the Sec17 crystal structure. The discontinuity in boxes or lines correspond to gaps in the alignment. b Residues that may participate in SNARE binding. Residues, mostly carrying a positive charge (see text), which occupy positions comparable to those of the SNARE-binding residues of the B. taurus α-SNAP have been mapped in blue onto the concave face of the threading models of both yeast and Giardia SNAPs. Residues that deviate from those of the B. taurus α-SNAP, either in terms of charge (GL50803_17224) or position (GL50803_16521 and GL50803_10856), have been marked with dotted circles