Extended Data Fig. 8: Sequence conservation and structural relevance of retrieved AHSG peptides.
From: Enamel proteome shows that Gigantopithecus was an early diverging pongine
All AHSG-specific peptides, identified by PEAKS and MaxQuant, derive from a single sequence region bridging cystatin domains 1 and 2. The surviving sequence region is evolutionarily conserved across Catarrhini. It contains a regular repeat of acidic amino acid residues (aspartic acid, D, on positions 133, 137 and 141) that enable binding of basic calcium phosphate (residues highlighted in green), similarly to a conserved region just N-terminal (glutamic acid, E, on position 111, and aspartic acid, D, on position 113 and 115). At the bottom, a fragment ion alignment is given of MaxQuant-identified AHSG peptides. The serine is phosphorylated in all matching spectra. The majority-based amino acid consensus sequence for the alignment of Catarrhini is shown at the top for amino acid positions 100–149 (amino acid coordinates following UniProt accession P02765 [FETUA_HUMAN]).
