Figure 6.

Alignment of the syntenic SLS loci in kinetoplastid protozoa. A, sequence alignments of the kinetoplastid SLS orfs in the regions of Loop 3 and Loop 5 according to experimentally determined catalytic activity classes of the T. b. brucei enzymes. All sequences are aligned to the corresponding experimentally defined Lister Strain 427 TbSLSs (top in each case). Residues that were subject to experimental mutation as described in the text are numbered. Closed circles; reciprocal mutation between TbSLS1 and TbSLS3. Open circles; reciprocal mutation between TbSLS2 and TbSLS4. Stars indicate the HDD triad (black). Red, conserved SM/EPC synthase residues. Green, conserved IPC synthase residues. Blue, shared SM/EPC and IPC synthase residues. Purple, unique EPC synthase residues. Yellow, unique LmjIPCS and TcSLS1 residues. Percent identity (%ID) within each activity class relative to the TbSLS type sequence is indicated. Divergent C-terminal amino acid sequences following the last common residue (TbSLS1-4, N296) were deleted for generation of the identity matrix. Experimentally confirmed and in silico activities are indicated. TbSLS sequence conservation between different activity classes was ~90% in all cases. T. vivax SLS1 identity versus all TbSLS activity groups was ~50%. B, alignment of the SLS loci from the assembled kinetoplastid genomes. Flanking orthologous conserved hypothetical genes set the common boundary for each locus. Experimentally confirmed SLS activities are denoted in black below each orf. Predicted activities based on loops 3 and 5 are indicated in red. Note that TgSLS7 of the T. b. gambiense locus is a pseudogene, and the T. cruzi locus contains an inserted trans-sialidase (TS) pseudogene. A & B. TriTryp database accession numbers are: T. b. brucei, TbSLS1-4, Tb427tmp.211.1000-Tb427tmp.211.1030; T. b. gambiense, TgSLS1-8, Tbg972.9.5370-Tbg972.9.5300; T. cruzi, TcSLS1, Tc00.1047053506885.124; T. vivax, TvSLS1, TvY486_0904020; L. major, LmIPCS, LmjF35.4990.