SBF, BDB, Makale Koleksiyonuhttps://hdl.handle.net/20.500.12403/18842024-03-29T14:02:03Z2024-03-29T14:02:03ZRecent Advances in the Analysis of Macromolecular Interactions Using the Matrix-Free Method of Sedimentation in the Analytical UltracentrifugeHarding, S.E., Gillis, R.B., Almutairi, F., Erten, T., Kök, M.Ş., Adams, G.G.,https://hdl.handle.net/20.500.12403/22842020-12-04T09:45:48Z2015-01-01T00:00:00ZRecent Advances in the Analysis of Macromolecular Interactions Using the Matrix-Free Method of Sedimentation in the Analytical Ultracentrifuge
Harding, S.E., Gillis, R.B., Almutairi, F., Erten, T., Kök, M.Ş., Adams, G.G.,
Sedimentation in the analytical ultracentrifuge is a matrix free solution technique with no immobilisation, columns, or membranes required and can be used to study self-association and complex or “hetero”-interactions, stoichiometry, reversibility and interaction strength of a wide variety of macromolecular types and across a very large dynamic range (dissociation constants from 10−12 M to 10−1 M). We extend an earlier review specifically highlighting advances in sedimentation velocity and sedimentation equilibrium in the analytical ultracentrifuge applied to protein interactions and mucoadhesion and to review recent applications in protein self-association (tetanus toxoid, agrin), protein-like carbohydrate association (aminocelluloses), carbohydrate-protein interactions (polysaccharide-gliadin), nucleic-acid protein (G-duplexes), nucleic acid-carbohydrate (DNA-chitosan) and finally carbohydrate-carbohydrate (xanthan-chitosan and a ternary polysaccharide complex) interactions
2015-01-01T00:00:00ZHydrodynamic characterisation of chitosan and its interaction with two polyanions: DNA and xanthanAlmutairi, F., Erten, T., Adams G.G., Hayes, M., McLoughlin P., Kök, M.Ş., Mackie, A.R.,Rowe, A., Harding, S.E.https://hdl.handle.net/20.500.12403/22832020-12-04T09:40:43Z2015-01-01T00:00:00ZHydrodynamic characterisation of chitosan and its interaction with two polyanions: DNA and xanthan
Almutairi, F., Erten, T., Adams G.G., Hayes, M., McLoughlin P., Kök, M.Ş., Mackie, A.R.,Rowe, A., Harding, S.E.
Chitosan, a soluble polycationic derivative of insoluble chitin, has been widely considered for use in the food, cosmetic and pharmaceutical industries. Commercial (“C”) and in-house laboratory (“L”) prepared chitosan samples extracted from crustaceous shells with different molecular weight and degrees of acetylation (25% and 15%) were compared with regards to (i) weight–average molecular weight (Mw); (ii) sedimentation coefficient (so20,w) distribution, and (iii) intrinsic viscosity ([η]). These parameters were estimated using a combination of analytical ultracentrifugation (AUC), size exclusion chromatography coupled to multi-angle laser light scattering (SEC–MALS) and differential pressure viscometry. Polydisperse distributions were seen from sedimentation coefficient distributions and elution profiles from SEC–MALS. Mw values obtained for each sample by sedimentation equilibrium measurements were in excellent agreement with those obtained from SEC–MALS. Mark–Houwink–Kuhn–Sakurada (MHKS) and Wales van Holde analyses of the data all suggest a semi-flexible conformation.
The principle of co-sedimentation was then used to monitor the interactions of the two different molecular weights of L chitosans with two polyanions, DNA and xanthan (another double helical high molecular weight molecule). Interactions were clearly observed and then quantified from the changes in the sedimentation coefficient distribution of the mixture compared to unmixed controls using sedimentation velocity. The interactions appeared to show a strong dependence on molecular weight. The relevance of this for DNA condensation applications is indicated.
2015-01-01T00:00:00ZComparative heterogeneity, molecular weights and viscosities of xanthans of different pyruvate and acetate contentErten, T., Adams, G.G., Foster, T.J., Harding, S.E.https://hdl.handle.net/20.500.12403/22822020-12-04T09:34:34Z2014-01-01T00:00:00ZComparative heterogeneity, molecular weights and viscosities of xanthans of different pyruvate and acetate content
Erten, T., Adams, G.G., Foster, T.J., Harding, S.E.
Introduction: The bacterial exopolysaccharide xanthan is a well-known hydrocolloid, with a high viscosity deriving from its large molecular weight and volume.
Materials and methods: Four different xanthans deriving from Xanthomanas campestris e two with
similar pyruvate and acetate contents and two with different contents e were characterized in dilute
aqueous buffered solution (pH 7.0, ionic strength 0.3 M) using sedimentation velocity and sedimentation
equilibrium in the analytical ultracentrifuge, supplemented by dynamic light scattering.
Results: This facilitated a comparison with regards heterogeneity (sedimentation coefficient distribution)
and molecular weight, despite their large size and low critical overlap concentration. The xanthans were
also compared with regard to reduced specific and intrinsic viscosity behaviour. The xanthans generally
show strong similarity in properties with the exception of the lowest pyruvate xanthan, a finding which
should be useful for future applications of these materials.
2014-01-01T00:00:00ZUltracentrifuge Methods for the Analysis of Polysaccharides, Glycoconjugates, and LigninsHarding, S.E., Adams, G.G., Almutairi, F., Alzahrani, Q., Erten, T., Kök, M.Ş., Gillis, R.https://hdl.handle.net/20.500.12403/22812020-12-04T09:29:00Z2015-01-01T00:00:00ZUltracentrifuge Methods for the Analysis of Polysaccharides, Glycoconjugates, and Lignins
Harding, S.E., Adams, G.G., Almutairi, F., Alzahrani, Q., Erten, T., Kök, M.Ş., Gillis, R.
Although like proteins, polysaccharides are synthesized by enzymes, unlike proteins there is no template. This means that they are polydisperse, do not generally have compact folded structures, and are often very large with greater nonideality behavior in solution. This chapter considers the relevant analytical ultracentrifuge methodology available for characterizing these and related carbohydrate-based systems and information this methodology supplies, in terms of sizes, shapes, and interactions using a comprehensive range of examples, including glycoconjugates and lignins. The relevance and potential of recent software developments such as SEDFIT-MSTAR, the Extended Fujita algorithm, and HYDFIT are considered.
2015-01-01T00:00:00Z