Crystal and molecular structure of V-amylose complexed with butan-1-ol

• Published in: Polymer (Guilford) 2022-03, Vol.243, p.124651, Article 124651
• Main Authors: Le, Cong Anh Khanh, Mazeau, Karim, Nishiyama, Yoshiharu, Ogawa, Yu, Choisnard, Luc, Wouessidjewe, Denis, Putaux, Jean-Luc
• Format: Article
• Language: English
• Subjects: Amylose; Aqueous solutions; Butan-1-ol; Chemical Sciences; Cristallography; Crystal structure; Crystals; Diffraction patterns; Handedness; Helices; Inclusion compounds; Lamellar structure; Molecular structure; Polymers; Single crystals; Structure refinement; Unit cell; V-amylose; Water chemistry; X-ray diffraction
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/j.polymer.2022.124651

Chain-folded lamellar V-amylose single crystals were prepared by adding butan-1-ol to hot dilute aqueous solutions of native amylose. The base-plane electron and X-ray diffraction patterns recorded from hydrated specimens agreed with a P212121 space group and an orthorhombic unit cell. A molecular model resulting from an exhaustive search of helix position and restrained structure refinement against diffraction data was proposed. The unit cell contains 4 antiparallel left-handed 6-fold amylose single helices with 1 butan-1-ol molecule located inside each of the helical cavities. In addition, 4 butan-1-ol and 20 water molecules are distributed in the 4 interstitial spaces. The amylose helices form rows along the b-axis that are alternatively shifted by ±b/8 with respect to one another, which validates the geometrical model proposed by Helbert and Chanzy in 1994. [Display omitted] •Native amylose formed chain-folded lamellar co-crystals with butan-1-ol.•Electron and X-ray diffraction data confirmed the orthorhombic unit cell.•The possible packing of amylose helices and guest distribution were explored.•Butan-1-ol molecules are located inside 6-fold amylose helices and in-between.•The results validate the geometrical model proposed by Helbert and Chanzy.