Two different molecular conformations found in chitosan type II salts.
The type II structure of chitosan acidic salts prepared from crab tendon in solid state was studied using an X-ray fiber diffraction technique together with the linked-atom least-squares (LALS) technique. The cylindrical Patterson method was applied to confirm the molecular conformation of the chitosan. It was shown that there are two different helical conformations for type II salts. One is the relaxed twofold helix having a tetrasaccharide as an asymmetric unit as found in chitosan.HCl salt, which was previously reported as a conformation of chitosan.HCOOH salt. The other is the fourfold helix having a disaccharide as an asymmetric unit newly found in chitosan.HI salt.
Faculty of Technology, Tokyo University of Agriculture and Technology, Koganei, 184-8588, Tokyo, Japan.
Amornrat
A
Lertworasirikul
Shin-ichiro
S
Tsue
Keiichi
K
Noguchi
Kenji
K
Okuyama
Kozo
K
Ogawa
D002236:Carbohydrate Conformation; D002686:Chitin / Q000031:analogs & derivatives* / Q000737:chemistry*; D048271:Chitosan; D003460:Crystallization; D006860:Hydrogen Bonding; D012492:Salts / Q000737:chemistry; D014961:X-Ray Diffraction / Q000379:methods
D012492:Salts; D002686:Chitin; D048271:Chitosan