With regards to the tetrasaccharide portion, stereochemistry and functionality can differ at R1 and R2 depending on if this saccharide unit is D-gluco versus D-galacto; there is an axial methyl group in the former case with the exception of moenomycin A12 and C1 where there is instead an axial hydroxyl. The oligosaccharide motif can be deoxygenated, hydroxylated, or glycosylated at the R3 position – notable examples of the pentasaccharide motif include moenomycin A and AC326-α. It is believed the additional glycan can enhance specificity and binding to the target protein, affording increased activity.[6] With the exception of pholipomycin and AC326-α, the R4 saccharide unit is usually the deoxysaccharide.