Structural properties of polyC–scleroglucan complexes

Abstract

Successive changes of solvent conditions can be used to dissociate and reassociate the triple-helical structure of (1,3)-beta-D-glucans. Ultramicroscopic techniques have revealed a blend of circular and other structures following renaturation. When this solvent exchange process is carried out in the presence of certain polynucleotides, the process creates a novel macromolecular complex. Here, we use size exclusion chromatography (SEC) to study such (1,3)-beta-D-glucan-polynucleotide complexes. Online multi-angle laser-light scattering (MALLS) and refractive index (RI) detectors allowed determination of molecular weight and radius of gyration of the molecules. An ultraviolet (UV) detector allowed specific detection of the polynucleotide. The poly-cytidylic acid (poly C) shifted to coelution with the linear fraction of the scleroglucan following the renaturation of poly C-scleroglucan blends, indicating that poly C is incorporated in linear, but not in circular, structures of scleroglucan. This conclusion was consistent with AFM topographs that revealed a decreased fraction of circular structures upon addition of poly C during the renaturation process. The combined information about radius of gyration (R(g)) and molecular weight (M(w)) allowed us to conclude that the poly C-scleroglucan complexes are more dense and have a higher persistence length than linear scleroglucan triple helixes. The experimentally determined mass per unit length was used as a basis for elucidating possible molecular arrangements within the poly C-scleroglucan complex.

Higher order structure of (1,3)‐β‐D‐glucans and its influence on their biological activities and complexation abilities

“…The formation of a complex between (1,3)‐β‐ D ‐glucans and certain polynucleotides88–92 opens for the use of (1,3)‐β‐ D ‐glucans as carriers for polynucleotides. The potential of (1,3)‐ β‐ D ‐glucan‐polynucleotide complexes for gene delivery purposes has also been reported93–95 and recently reviewed 24.…”

Characterization of High-Molecular-Weight Nonnative Aggregates and Aggregation Kinetics by Size Exclusion Chromatography With Inline Multi-Angle Laser Light Scattering

“…By combining the above analytical features, traditional SEC coupled with an inline MALS detector (SEC‐MALS) has been a popular choice for qualitative and semi‐quantitative product characterization in pharmaceutical, agricultural, and medical applications 29, 32–36. It has been applied to a variety of bio‐molecules including proteins,36 carbohydrates,37 polysaccharides,38 viral particles,39 and nucleotides 40. A primary advantage over traditional SEC is that SEC‐MALS provides absolute M w without the need of size calibration.…”

Structure–Function Relationships in Glycopolymers: Effects of Residue Sequences, Duplex, and Triplex Organization

“…Based on those publications, we explored whether the application of ultramicroscopy combined with multidetector chromatography could provide further information. Our result indicated that poly‐cytidylic acid (polyC) was included in the linear and not the macrocyclic structures of scleroglucan after renaturation . The l p s of polyC–scleroglucan complexes were exceeding that of the (1,3)‐β‐ d glucan triplex.…”