Single crystals of amylose V complexes. III. Crystals with 81 helical configuration

Authors:
Publisher website
Google Scholar
Abstract
Single crystals of amylose V complexes with the 81 helical configuration can be obtained from aqueous solutions of amylose by using α‐naphthol as a complexing agent. Morphological observations suggest that the differences in crystallization behavior among the α‐naphthol complex and other complexes with alcohols are due to differences in solubility of the complexes in water. Electron diffraction studies indicate a two‐dimensional tetragonal unit cell with a = b = 22.9 Å. It is deduced that the space group providing a satisfactory arrangement of two helices is one of the enantiomorphs P41212 and P43212. From x‐ray diffraction it was found that the c axis spacing of the α‐naphthol complex is equivalent to that in 61 and 71 helical amylose crystals. Consequently, the geometry of the helical configuration requires an integral number of glucose residues per turn. The true helical diameters of the n‐butanol, isopropanol, and α‐naphthol complexes were calculated from experimental data. The ratio was 6:7:8 and indicated that the helix of the α‐naphthol complex has eight glucose residues per turn. The diversity of helical configurations in V amylose crystals is discussed.

This publication has 13 references indexed in Scilit: