Polymeric properties of k-carrageenan chains at different temperatures: its dependence with the regions visited by the Molecular dynamics simulation

MYRIAM VILLEGAS, SILVINA GUIDUGLI, CARMEN ESTEBAN, CECILIA FERNÁNDEZ GAUNA, SERGIO PANTANO, SERGIO PAOLETTI AND JULIO BENEGAS.

Montevideo, Uruguay

Congreso; 6th International Conference of Biological Physics, 5th Southern cone Biophysicl Congress, 34th annual meeting of the argentineanBiophysical Society. ICBP 2007; 2007

International Conference of Biological Physics

K-carrageenans are one of the most widely known and commercially exploited red-algae sulfated galactans. One of the most peculiar features is related to its ability to give rise to ionotropic gels, in particular with alkaline metal counter ions of high atomic number. Such gels are thermoreversible, like other related polysaccharides like i-carrageenans and agarose. The detailed molecular interpretation for the gelation mechanism of k-carrageenans has been highly controversial for more than two decades. Nowadays it is accepted that a disorder to order conformational transition of the individual polysaccharide chains underlies the physical gelation mechanism. This disorder to order conformational transition is usually driven by the dependence on the temperature of the interactions determining the polymeric chain spatial conformation. In the present work the results of Molecular Dynamics simulations of a decamer of k-carrageenan disaccharide repeating unit are used to generate polymer chains of different lengths in order to characterize the polymeric properties of such chains. The study is carried out at two different temperatures with the aim of determining the characteristics of the temperature-driven conformational transition. In this approach we also study the consequences of building polymeric chains selecting states belonging to the different (F,Y) regions visited by the corresponding molecular simulation.