ABSTRACT
The structural characterization of carbohydrate polymers is important for understanding their functions and behavior. However, mainstream structural biology tools are not applicable to many carbohydrate polymers, particularly at physiological concentrations. We report Raman and Raman optical activity spectra of hyaluronan polymer, the hyaluronan tetramer building block, and the two monosaccharide components glucuronic acid and N-acetylglucosamine and identify marker bands corresponding to primary and secondary structure in glycosaminoglycans. Furthermore, we show that the hyaluronan polymer does not adopt tertiary structure under near-physiological conditions, confirming a proposed model of hyaluronan structural organization.
Subject(s)
Hyaluronic Acid/chemistry , Polymers/chemistry , Carbohydrate Conformation , Spectrum Analysis, RamanABSTRACT
In most optimisation experiments, a single parameter is first optimised before a second and then third one are subsequently modified to give the best result. By contrast, we believe that simultaneous multiobjective optimisation is more powerful; therefore, an optimisation of the experimental conditions for the colloidal SERS detection of L-cysteine was carried out. Six aggregating agents and three different colloids (citrate, borohydride and hydroxylamine reduced silver) were tested over a wide range of concentrations for the enhancement and the reproducibility of the spectra produced. The optimisation was carried out using two methods, a full factorial design (FF, a standard method from the experimental design literature) and, for the first time, a multiobjective evolutionary algorithm (MOEA), a method more usually applied to optimisation problems in computer science. Simulation results suggest that the evolutionary approach significantly out-performs random sampling. Real experiments applying the evolutionary method to the SERS optimisation problem led to a 32% improvement in enhancement and reproducibility compared with the FF method, using far fewer evaluations.
