Cation-specific aggregation of carrageenan helices: Domain model of polymer gel structure

Morris, Edwin R.; Rees, David A.; Robinson, Geoffrey

doi:10.1016/0022-2836(80)90291-0

Cited by 540 publications

(231 citation statements)

References 30 publications

Supporting

Mentioning

210

Contrasting

Unclassified

Order By: Relevance

“…The gel properties of carrageenans are also strongly dependent on the presence of salts and on the ionic strength of the medium [5]. With three sulfate groups per carrabiose unit, λ-carrageenan is the most negatively charged galactan from red algae.…”

Section: Introductionmentioning

confidence: 99%

Degradation of λ-carrageenan by Pseudoalteromonas carrageenovora λ-carrageenase: a new family of glycoside hydrolases unrelated to κ- and ι-carrageenases

Guibet¹,

Colin²,

Barbeyron³

et al. 2007

Biochem. J.

View full text Add to dashboard Cite

Carrageenans are sulfated galactans found in the cell walls of red seaweeds. They are classified according to the number and the position of sulfate ester groups. lambda-Carrageenan is the most sulfated carrageenan and carries at least three sulfates per disaccharide unit. The sole known depolymerizing enzyme of lambda-carrageenan, the lambda-carrageenase from Pseudoalteromonas carrageenovora, has been purified, cloned and sequenced. Sequence analyses have revealed that the lambda-carrageenase, referred to as CglA, is the first member of a new family of GHs (glycoside hydrolases), which is unrelated to families GH16, that contains kappa-carrageenases, and GH82, that contains iota-carrageenases. This large enzyme (105 kDa) features a low-complexity region, suggesting the presence of a linker connecting at least two independent modules. The N-terminal region is predicted to fold as a beta-propeller. The main degradation products have been purified and characterized as neo-lambda-carratetraose [DP (degree of polymerization) 4] and neo-lambda-carrahexaose (DP6), indicating that CglA hydrolyses the beta-(1-->4) linkage of lambda-carrageenan. LC-MALLS (liquid chromatography-multi-angle laser light scattering) and (1)H-NMR monitoring of the enzymatic degradation of lambda-carrageenan indicate that CglA proceeds according to an endolytic mode of action and a mechanism of inversion of the anomeric configuration. Using 2-aminoacridone-labelled neo-lambda-carrabiose oligosaccharides, in the present study we demonstrate that the active site of CglA comprises at least 8 subsites (-4 to +4) and that a DP6 oligosaccharide binds in the subsites -4 to +2 and can be hydrolysed into DP4 and DP2.

show abstract

Section: Introductionmentioning

confidence: 99%

Degradation of λ-carrageenan by Pseudoalteromonas carrageenovora λ-carrageenase: a new family of glycoside hydrolases unrelated to κ- and ι-carrageenases

Guibet¹,

Colin²,

Barbeyron³

et al. 2007

Biochem. J.

View full text Add to dashboard Cite

show abstract

“…On heating, the helices dissolve and the ι-carrageenan forms a random coil conformation [4]. Intermolecular double helix formation should result in a doubling in the observed molecular weight of the ι-carrageenan, which has been observed in many groups [2,5]. However some authors have proposed monomolecular single-helix formations [6].…”

Section: Introductionmentioning

confidence: 99%

“…Iota carrageenan is the most highly sulphated of the helix-forming polysaccharides and is also the most fully characterized in the solid state and in solution [2]. This type of carrageenan is extensively used as gelling agent in food and pharmaceutical formulations.…”

Section: Introductionmentioning

confidence: 99%

“…It is well known that iota carrageenan forms a three dimensional network constituted of polysaccharide chains structured as double helices. This gelation is induced by cooling heated suspensions of the polysaccharide in water under appropriate salt conditions resulting in a coil-helix conformational transition [2,3]. It has been known that in solution, ι-carrageenan can reversibly transform from an ordered to a disordered conformation.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Swelling of iota-carrageenan gels prepared with various CaCl2 content: A fluorescence study

Tarı

Pekcan

2008

E-Polymers

View full text Add to dashboard Cite

Iota carrageenan gels prepared with various CaCl 2 content were completely dried and then swelled in water vapor. Steady-state fluorescence (SSF) technique was used to monitor the swelling process of each iota carrageenan gels at various temperatures. Pyranine was used as a fluorescence probe. Apparent fluorescence intensity, I increased as swelling time increased for all gel samples. The increase in I was modelled using Li-Tanaka equation from which the swelling time constants, τ 1 and cooperative diffusion coefficients, D c were determined. It was observed that D c increased as the swelling temperature was increased. On the other hand at each temperature, it was seen that D c decreased as CaCl 2 content was increased. Activation energies for swelling were obtained and found to be 60.5, 61.0, 61.5 and 62.8 kJmol -1 for the gels prepared with increasing amount of CaCl content.

show abstract

“…It was recognized in the present work that the water-soluble jelly fig polysaccharide molecule was in a contracted state from the indicated exponent of 0.37 by association under the influence of the inherent inorganic ions in the extraction processes, because no inorganic ions were added to the extract. It is also considered that the water-soluble jelly fig polysaccharide with a straihgt-chain molecule formed a double helix in the same way as that in the gelation mechanism for carageenan, 24,25) and aggregated by the effect of inherent K +. The galacturonic acids were then demethylated by the action of inhrent pectinesterase, and the molecule further contracted by associating with Ca 2 + .…”

Section: Constituents Of the Freeze-dried Samplesmentioning

confidence: 99%

Molecular Characteristics of Water-soluble Polysaccharide Extracted from Jelly Fig (Ficus awkeotsangMakino) Seeds

Suzuno

Kinugasa

Nakahara

et al. 1997

Bioscience, Biotechnology, and Biochemistry

View full text Add to dashboard Cite

Cation-specific aggregation of carrageenan helices: Domain model of polymer gel structure

Cited by 540 publications

References 30 publications

Degradation of λ-carrageenan by Pseudoalteromonas carrageenovora λ-carrageenase: a new family of glycoside hydrolases unrelated to κ- and ι-carrageenases

Degradation of λ-carrageenan by Pseudoalteromonas carrageenovora λ-carrageenase: a new family of glycoside hydrolases unrelated to κ- and ι-carrageenases

Swelling of iota-carrageenan gels prepared with various CaCl2 content: A fluorescence study

Molecular Characteristics of Water-soluble Polysaccharide Extracted from Jelly Fig (Ficus awkeotsangMakino) Seeds

Contact Info

Product

Resources

About