Multistranded helix in xanthan polysaccharide

The extracellular polysaccharide xanthan is shown by electron microscopy to be an unbranched, probably double-stranded fiber 4 nanometers wide and 2 to 10 micrometers long when native. Denaturation yields a single strand only 2 nanometers wide and 0.3 to 1.8 micrometers long. Renatured xanthan shows short unraveled regions with two or three strands arranged in a right-handed twist.