Morphological and structural studies of poly(gly‐gly‐ala)

The ultrastructural morphology and x‐ray and electron diffraction of poly (Gly‐Gly‐Ala) have been studied. The polymer has two forms; the first, form I possesses a super‐folded cross‐β structure, long fibers of which show some twisting and intertwining. Form II precipitates in a less distinct fibrous form from aqueous solution. The x‐ray diffraction and oriented electron diffraction data suggest that form II is a polyglycine II helix situated in a monoclinic cell with dimensions a = 8.86 Å, b = 22.0 Å, c = 9.42 Å, and β = 90°. Combined with the morphological evidence it appears likely that form II is also in an antiparallel superfolded array.