Figure 1.

Polypeptides 1–4 were prepared by total synthesis and represent clustered α- and β-O-linked glycodomains. The sequence STTAV is in the amino terminus of the protein CD43. The glycans, indicated as R, are known tumor antigens. The STF trisaccharide antigen of 1 is present on CD43 when expressed on acute myelogenous leukemia cells. The TF antigen of 2 and Tn antigen of 3 are expressed on certain malignant carcinomas, particularly of the prostate and colon. Constructs 1–3 contain the natural mucin α-O-GalNAc core. Construct 4 was prepared for comparison and has the unnatural β-linkage.