The molecule is a tetrasaccharide consisting of three beta-D-galactopyranosyl residues and a D-glucopyranosyl residue joined in sequence by three (1->4) glycosidic bonds. It derives from a beta-D-Galp-(1->4)-beta-D-Galp-(1->4)-D-Glcp and a beta-(1->4)-galactotriose.
(2S,3R,4S,5R,6R)-2-[(2R,3R,4R,5R,6S)-6-[(2R,3R,4R,5R,6S)-4,5-dihydroxy-2-(hydroxymethyl)-6-[(2R,3S,4R,5R)-4,5,6-trihydroxy-2-(hydroxymethyl)oxan-3-yl]oxyoxan-3-yl]oxy-4,5-dihydroxy-2-(hydroxymethyl)oxan-3-yl]oxy-6-(hydroxymethyl)oxane-3,4,5-triol