Hyaluronan-Arginine Interactions—An Ultrasound and ITC Study

Abstract

High-resolution ultrasound spectroscopy and isothermal titration calorimetry were used to characterize interactions between hyaluronan and arginine oligomers. The molecular weight of arginine oligomer plays an important role in interactions with hyaluronan. Interactions were observable for arginine oligomers with eight monomer units and longer chains. The effect of the ionic strength and molecular weight of hyaluronan on interactions was tested. In an environment with increased ionic strength, the length of the arginine oligomer was crucial. Generally, sufficiently high ionic strength suppresses interactions between hyaluronan and arginine oligomers, which demonstrated interactions in water. From the point of view of the molecular weight of hyaluronan, the transition between the rod conformation and the random coil conformation appeared to be important.

Computational Study of Complex Formation between Hyaluronan Polymers and Polyarginine Peptides at Various Ratios

“…This indicates that the concentration of Cl ions surrounding the peptides was higher compared to the bulk solution, enabling the formation of a negatively charged layer. This layer, in turn, hindered the attraction of Arg to the HA surface (as shown in Figure S4D), confirming experimentally determined weaker interaction between HA and Arg, 14 and ultimately resulted in the formation of linearly extended complexes between HA and polyarginine (Figure S3D).…”

“…The modeling study could not directly address the impact of HA conformation (linear or rod-like versus bent) on high molecular weight HA, as discussed in the experimental work. 14 This limitation arose from the relatively short length of the longest HA model that could be handled in the study.…”

“…Notably, the specific conformations adopted by hyaluronan and arginine oligomers were also found to play a significant role in the interactions. 14 In order to gain insights into the dynamics of HA− polyarginine complex formation and to assess the interactions between HA and polyarginine peptides of varying lengths, this study employed computational modeling and molecular dynamics simulations (MD). Furthermore, the findings of this theoretical investigation were validated by comparing them with the experimental results.…”

Interactions between Cationic Ion Pair Amphiphile Vesicles and Hyaluronan—A Physicochemical Study

“…Generally, the ultrasound velocity decreased during the hyaluronan addition in the interaction area (2 and most of 3 in Figure ), which points to the formation of less rigid structures. This is probably due to the release of the hydration water molecules upon interaction; hydration water is known to be less compressible . The reincrease of the velocity at the end of 3 and during 4 in Figure is due to the dissolution of flocs and particles, causing the turbidity to be observed visually (Figures and S1 in the Supporting Information).…”

High-Resolution Ultrasonic Spectroscopy: Looking at the Interpolyelectrolyte Neutralization from a Different Perspective

“…Therefore, HR-US is a very versatile method that can be used to analyze a broad range of molecular processes. Current applications of this technique include analysis of aggregation, micellization, and gelation phenomena, − phase diagrams of microemulsions, conformational transitions in polymers and biopolymers, interactions between polyelectrolytes and surfactants or amino acids, − stability of emulsions and suspensions, − polymer adsorption onto surfaces, enzymatic hydrolysis of proteins and carbohydrates, ,− and many others. Despite being employed for the characterization of numerous chemical and physical processes, there is a lack in the literature regarding the potential use of HR-US for studying the formation of polyelectrolyte complexes.…”