title: Inulin isoforms differ by repeated additions of one crystal unit cell.
abstract: Inulin isoforms, especially delta inulin, are important biologically as immune activators and clinically as vaccine adjuvants. In exploring action mechanisms, we previously found regular increments in thermal properties of the seven-member inulin isoform series that suggested regular additions of some energetic structural unit. Because the previous isolates carried additional longer chains that masked defining ranges, these were contrasted with new isoform isolates comprising only inulin chain lengths defining that isoform. The new series began with 19 fructose units per chain (alpha-1 inulin), increasing regularly by 6 fructose units per isoform. Thus the 'energetic unit' equates to 6 fructose residues per chain. All isoforms showed indistinguishable X-ray diffraction patterns that were also identical with known inulin crystals. We conclude that an 'energetic unit' equates to one helix turn of 6 fructose units per chain as found in one unit cell of the inulin crystal. Each isoform chain comprised progressively more helix turns plus one additional fructose and glucose residues per chain.
authors: Vaxine Pty Ltd, Flinders Medical Centre, Bedford Park, SA 5042, Australia; Cancer Research Laboratory, Australian National University Medical School at The Canberra Hospital, Garran, ACT 2605, Australia; John Curtin School of Medical Research, The Australian National University, Acton, ACT 2601, Australia. Electronic address: peter.cooper@anu.edu.au.
authors: Peter D
authors: PD
authors: Cooper
authors: The Mawson Institute, University of South Australia, Mawson Lakes, SA 5095, Australia.
authors: Thomas G
authors: TG
authors: Barclay
authors: The Mawson Institute, University of South Australia, Mawson Lakes, SA 5095, Australia.
authors: Milena
authors: M
authors: Ginic-Markovic
authors: The Mawson Institute, University of South Australia, Mawson Lakes, SA 5095, Australia.
authors: Andrea R
authors: AR
authors: Gerson
authors: Vaxine Pty Ltd, Flinders Medical Centre, Bedford Park, SA 5042, Australia; Department of Endocrinology, Flinders Medical Centre/Flinders University, Bedford Park, SA 5042, Australia. Electronic address: nikolai.petrovsky@flinders.edu.au.
authors: Nikolai
authors: N
authors: Petrovsky
mesh_terms: D003460:Crystallization; D007444:Inulin / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D007444:Inulin
keywords: Adjuvant; Carbohydrate; Inulin; Isoform; Polymorph; Vaccine