X-RAY DIFFRACTION OF ORIENTED AMYLOSE FIBERS .2. STRUCTURE OF V AMYLOSES

Oriented amylose fibers in the V form were prepared and subjected to X-ray analysis. Unit cells and the probable space group of P21P21P21 were determined for the V anhydrous and V hydrate forms of amylose; the analysis confirms previous predictions of these structures based on X-ray powder patterns. Chain folding in V amyloses is discussed in view of crystallographic evidence and folding experiments conducted with space-filling models. Reported also in evidence for amylose helices having diameters intermediate between 13.0 and 13.7 A.