O(3)-(beta-D-galactosyl-(1->3)-N-acetyl-alpha-D-galactosaminyl)-L-serine residue
o(3)-(beta-d-galactosyl-(1->3)-n-acetyl-alpha-d-galactosaminyl)-l-serine residue
An <small>L</small>-α-amino acid residue derived from <em>O</em><small><sup>3</small></sup>-(β-<small>D</small>-galactosyl-(1→3)-<em>N</em>-acetyl-α-<small>D</small>-galactosaminyl)-<small>L</small>-serine.