Conformation carrageenan

Ciencia M.M., Milas M., Rinaudo M., On the specific role of colons and counterions on kappa-carrageenan conformation, Int. J. Biol. MacromoL, 20,1997, 35-41. 

Fig. 4.19. i-Carrageenan conformation, a Double helix, b single coil is presented to clarify the conformation (according to Rees, 1977)... 

Carrageenans and alginates present different conformations egg-box structure (alginates) and double helices (carrageenan) but both natural biopolymers are able to form gels and consequently, to control nanoparticle growth. 

Grasdalen, H. and Smidsrod, O. (1981) Iodide-specific formation of K-carrageenan single helices-1-127 NMR spectroscopic evidence for selective site binding of iodide anions in the ordered conformations. Macromolecules, 14, 1842-1845. 

Hjerde, T., Smidsrad, O., Christensen, B.E. (1998a). Analysis of the conformational properties of k- and i-carrageenan by size-exclusion chromatography combined with low-angle laser light scattering. Biopolymers, 49, 71-80. 

N 137 "Conformational Analysis of Polysaccharides, Part II. Alternating Copolymers of the Agar-Carrageenan-Chondroitin type by Model Building in the... 

Model building in the computer is used to analyze the conformational effects of steric interactions between atoms of the polymer skeleton for x-carrageenan, t-carrageenan, A-carrageenan, agar, chondroltin, chondroitin sulfates, dermatan sulfate, keratan sulfate, hyaluronic acid, and related polysaccharides. Over 99% of the conformations are thus excluded and virtually all of the remainder for each polysaccharide lie close together. Predictions are also made from disaccharide crystal structures and checked against experimental results. 

An enzyme that is involved in the biosynthesis of carrageenan has been detected in seaweed extracts.387 It converts 6-O-sulfo-D-galactosyl into 3,6-anhydro-D-galactosyl units at the polymer level, and this structural change significantly affects gelling properties that depend on conformation.384... 

Rees et al. (25) have extensively examined the solution conformation and interactions of a number of polysaccharides, especially carrageenan fractions. Kappa-carrageenan is unusual as it forms gels when a solution of its potassium salt is cooled. Rees conceives that double helix formation occurs in solution and, interlocking helices develop in the gel state. 

A viscoelastic fluid has the appearance of a solid body it deforms and wholly recovers below t0, and only partly recovers above t0. From 0 to t0, the fluid undergoes an elastic conformational transition above t0, the fluid undergoes an irreversible transition, whence the mass begins to flow toward a new equilibrium position. Carrageenan-water-polyol systems have been suggested to be industrially useful in consideration of their significant t0 followed by shear-thinning (Tye, 1988). 

Dea, I. C. M., McKinnon, A. A., and Rees, D. A. (1972). Tertiary and quaternary structure in aqueous polysaccharide systems which model cell wall cohesion reversible changes in conformation and association of agarose, carrageenan and galactomannans. J. Mol. Biol. 68 153-172. 

A-Fl-FFF/MALLS has been used for the determination of the molar mass and size distribution of dextrans and pullulans of various molar masses [473], hy-droxypropylmethylcelluloses [474] and K-carrageenan in different conformations and aggregation states [475]. 

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