FIGURE 8.

Proposed structures and biosynthetic pathways for HMOCC-1 antigens. The absence of CHST1 and GAL3ST3 adds sulfate onto the Gal3 position of the LacNAc terminal. In the presence of CHST1, two types of sulfation occur, one at the terminal galactose (left) and the other at an internal galactose (right). Addition of sulfate to the Gal6 terminal (left) prohibits further modification by GAL3ST3. When sulfate is added to an internal Gal6, GAL3ST3 modifies the product by adding sulfate onto the Gal3 position of sulfated LacNAc, resulting in production of a strong HMOCC-1 antigen.