Fig. 6.

Conservation analysis of sialic acid synthase sequences and profiles. The sequences identified as NeuB in the KEGG database were divided into four groups: NeuB from pathogenic bacteria (n=169); NeuB from environmental bacteria with an SAF domain (n=242); and NeuB from Archaea (n=10). NanS sequences from eukaryotes were also retrieved from KEGG (n=160). Each group of sequences were aligned separately using MAFFT. The alignments were used to build a conservation profile for each group considering each amino acid residue in each position. The tree profiles were compared with the NeuB sequence of N. meningitidis and the NanS from Homo sapiens. The residues important for catalysis were identified by Gunawan et al.⁠ [19] based on the NeuB structure crystallized with its substrates ManNAc and PEP. The positions marked in blue in the N. meningitidis sequence represent the catalytic residues, while the positions marked in orange represent the non-catalytic residues. Green tagged residues in the profiles represent positions with at least 70 % conservation in the alignment. The amino acid residue positions listed in the alignment are related to NeuB of N. meningitidis . The NeuB domain and the SAF domain are indicated in the box above the alignment.