Characterization and protein modelling of buffalo S100A8 reveals conserved molecular structure in bovines

Abstract

S100A8, a calcium binding protein, is involved in various intracellular and extracellular functions. In this paper, we
characterized the complete cDNA sequence of the S100A8 molecule and modelled its protein structure in buffalo
(Bubalus bubalis). The structure was further compared with that of cattle to determine molecular homology. The
amino acid sequence of buffalo S100A8 was 89 residues long and showed 12 amino acid variations in comparison
to cattle. Sequence divergence of buffalo S100A8 with non-ruminants was higher than that of ruminant species.
Phylogenetic analysis revealed that buffalo and other ruminants were found to group together separated from
all other non-ruminants, including human. Physiochemical parameters of buffalo S100A8 showed comparatively
higher stability as well as structurally conserved protein structure. Comparative modelling, using cattle as a
reference, confirmed the high structural conservation of buffalo S100A8. Further, amino acid substitutions at
seven important locations of buffalo S100A8 (7, 11, 22, 23, 36, 68 and 81) did not appear to affect the protein
model with that of cattle. This study highlights the molecular structure of S100A8 in buffalo, demonstrating high
sequence homology and conserved protein architecture among bovines.