Preparation and characterization of curdlan with unique single-helical conformation and its assembly with Congo Red. (1st July 2021)

• Record Type: Journal Article
• Authors: Yan, Xiaoshuang; Liu, Biaolan; Ru, Geying; Feng, Jiwen
• Is Part Of: Carbohydrate polymers. Volume 263(2021)
• Publication Date: 2021-07-01
• Subjects: Curdlan -- Single-helical conformation -- NMR -- Supramolecular assembly; Polysaccharides -- Periodicals; Polysaccharides -- Periodicals; Polysaccharides -- Périodiques; Electronic journals; 547.78
• DOI: 10.1016/j.carbpol.2021.117985
• Languages: English
• ISSNs: 0144-8617

Abstract

Graphical abstract: Highlights: The unique, single-helical curdlan can be achieved in dilute NaOH aqueous solutions at 35−50 °C. The conformational transition and intramolecular hydrogen bond interaction of single-helical curdlan are revealed. The self-diffusion coefficient experiments indicate that single-helical curdlan chains translate together with Congo Red. 1D NOESY spectra show the distance between H3 among the H1-H6 of curdlan and phenyl groups of Congo Red is the shortest. Abstract: Elucidating the structure-activity relationship of curdlan is hampered by a lack of characterization with unique specific conformations (i.e., single- or triple-helix). In this study, single-helical curdlan is generated in dilute NaOH solutions at 35−50 °C, and characterized with NMR, SAXS, and GPC. The conformational transition from coil to single-helix and the intramolecular hydrogen bond interaction are explored using NMR. It is found that the two aforementioned types of curdlan interact with Congo Red in very different ways. Single-helical curdlan can encapsulate Congo Red to form a stable, supramolecular dye assembly, which is demonstrated by the shortest distance between the H3 of curdlan and the phenyl groups of Congo Red, and also the same self-diffusion coefficients of Congo Red and curdlan. In contrast, random-coil curdlan interacts weakly with Congo Red and cannot enwrap it. This study offers insight into the specific structure-activity relationship of beta-(1, 3)-glucans.