Conformational behavior of a gel-forming (1→3)-β-D-glucan in alkaline solution

Ogawa, K.; Wanatabe, Takehiko; Tsurugi, Jitsuo; Ono, Satoshi

doi:10.1016/s0008-6215(00)82709-3

Cited by 148 publications

(48 citation statements)

References 17 publications

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“…First, the large positive [a] 0 value for our glucan is comparable to that (195degcm 2 g-1 in IN aqueous NaOH) reported for a 3)-a-D-glucan from Agrocybe cylindracea by Kiho et a/. 15 Secondly, the normality 0.5N of aqueous NaOH is high enough to break the possible helical conformation of curdlan 16 and hence [a] 0 of -13degcm 2 g-1 for that glucan may be considered to contain no substantial contribution from the helical structure.…”

Section: Structure Of Water-insoluble Polysaccharidessupporting

confidence: 80%

Chemical Structure of the Water-Insoluble Polysaccharide Isolated from the Fruiting Body of Ganoderma lucidum

Chen

Zhou

Zhang

et al. 1998

Polym J

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Section: Structure Of Water-insoluble Polysaccharidessupporting

confidence: 80%

Chemical Structure of the Water-Insoluble Polysaccharide Isolated from the Fruiting Body of Ganoderma lucidum

Chen

Zhou

Zhang

et al. 1998

Polym J

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“…4). Previous studies reported that concentrations of NaOH greater than 0.24 M were required to convert triplehelix glucans to random coils (19,27), which subsequently would form single helices after removing NaOH (16). FRET would not occur if there was actual strand separation (random coil conformers) due to the relatively large distance between the donor and the acceptor probes.…”

Section: Resultsmentioning

confidence: 99%

Observation of a Partially Opened Triple-helix Conformation in 1→3-β-Glucan by Fluorescence Resonance Energy Transfer Spectroscopy

Young¹,

Dong²,

Jacobs³

2000

Journal of Biological Chemistry

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This study used fluorescence resonance energy transfer (FRET) spectroscopy as an indirect method to investigate the effect of NaOH treatment on the conformation of a triple-helix (133)-␤-D-glucan and then evaluated the effect of conformation on biological activity. Previous studies have suggested that treatment of the triple-helix glucans with NaOH produces single-helix conformers. FRET spectra of the triple-helix glucan, laminarin, doubly labeled with 1-aminopyrene as donor probe and fluorescein-5-isothiocyanate as acceptor probe attached at the reducing end, showed that a partially opened triplehelix conformer was formed on treatment with NaOH. Increasing degrees of strand opening was associated with increasing concentrations of NaOH. Based on these observations we propose that a partially opened triplehelix rather than a single helix, is formed by treating the triple-helix glucans with NaOH. After neutralizing the NaOH, changes in FRET indicated that the partially opened conformer gradually reverts to the triple-helix over 8 days. Laminarian was stabilized at different degrees of partial opening and its biological activity examined using the Limulus amebocyte lysate assay and nitric oxide production by alveolar macrophage. Both Limulus amebocyte lysate activity and nitric oxide production were related to the degree of opening of the triple-helix. Partially open conformers were more biologically active than the intact triple-helix.(133)-␤-D-Glucans have been shown to systemically enhance the immune system, resulting in antitumor, antibacterial, and wound healing activities (1). Differences in these activities are thought to be related to three factors: molecular conformation, the degree of branching, and the molecular weight (M r ) (2). Studies have shown that high M r (100,000 -200,000 g/mol) glucans with a degree of branching of 0.20 -0.33 are most active (2), however, data describing the effects of molecular conformation on biological activity are less clear. This is in part due to the lack of adequate methodology to characterize the tertiary structure of glucans.Most spectroscopic techniques only provide data about the secondary structure of glucans. Methods such as solid state 13 C NMR spectroscopy (3) or multi-angle laser-light scattering (4) have had some success in relating the tertiary structure of glucans to their conformation based biological activity, however, their use is limited by availability, cost, and efficacy for evaluating glucan structure in solution. A direct observation technique, such as x-ray crystallography would assist in understanding glucan structure and its biological relevance; however, it is difficult to crystallize glucans and only a limited number of these studies have been done (5-7).Fluorescence resonance energy transfer (FRET) 1 is a phenomenon of non-radioactive energy transfer over relatively long distances that has been used to characterize the spatial relationship of donor-and acceptor-labeled molecules in biological systems (8). If a system contains two fluorophores an...

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“…n +n r K D (3) where r represents the concentration ratio of the complex to the total glucan, CIR o . To get precise values of C and D we selected a wavelength of 540 nm where the largest difference of the absorbance between the complex and the free dye was observed (Fig.…”

mentioning

confidence: 99%

Dependence of Complex Formation of (1 → 3)-β-d-Glucan with Congo Red on Temperature in Alkaline Solutions

Ogawa

Dohmaru

Yui

1994

Bioscience, Biotechnology, and Biochemistry

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Conformational behavior of a gel-forming (1→3)-β-D-glucan in alkaline solution

Cited by 148 publications

References 17 publications

Chemical Structure of the Water-Insoluble Polysaccharide Isolated from the Fruiting Body of Ganoderma lucidum

Chemical Structure of the Water-Insoluble Polysaccharide Isolated from the Fruiting Body of Ganoderma lucidum

Observation of a Partially Opened Triple-helix Conformation in 1→3-β-Glucan by Fluorescence Resonance Energy Transfer Spectroscopy

Dependence of Complex Formation of (1 → 3)-β-d-Glucan with Congo Red on Temperature in Alkaline Solutions

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