Abstract: | The x-ray fiber diffraction pattern of the mannan I polymorph has been reexamined using the linked atom least squares (LALS) model-building program. The chain conformation and packing were refined using atomic coordinates derived from the x-ray crystallographic structure of mannotriose. The study confirmed the conclusions of previous investigations and showed that, in mannan I, the chains are antiparallel. Mannan polymorphism is compared with other related polysaccharides and the biological significance of this result in relation to the biosynthesis of mannan is discussed. |