The invention is based, at least in part, on the finding that linker peptides which lack the amino acid sequence GSG reduce or eliminate the addition of posttranslational modifications to the polypeptides which comprise them. More specifically, the novel linker peptides disclosed herein reduce the ability of enzymes to link carbohydrate adducts to polypeptides comprising these linker peptides, e.g., reduce the ability of xylosyltransferase to link xylose to polypeptides. These novel linker peptides, molecules comprising same, and methods of their use are described.