(510b) Molecular Aggregation of Biopolymers at High Pressures

Elastin is a major constituent of the biological elastic fibres in mammalian tissues that are under strong sustaining tension, such as aorta wall, lung and ligament. The highly insoluble extracellular matrix elastin is responsible for elasticity in these tissues. While many proteins denature upon increasing the temperature above 40°C, elastin is folded and the molecules are aggregated due to interaction via hydrophobic domains of the molecules. The complex behaviour of elastin as an elastomer has been intriguing and studies conducted to propose a model for its elastomeric function. However, due to insoluble characteristics of elastin, the physico-biochemical studies are confined. While elastin is insoluble, tropoelastin, the biogenic precursor protein of elastin (70 KDa) is soluble in water. Other soluble elastin such as α -elastin has also been introduced that is a hot oxalic acid fragmentation product of elastin with similar properties as tropoelastin. These biopolymers were used to investigate the behaviour of elastin.

The primary objective of this study was to investigate for the first time the effect of pressure on the molecular aggregation of tropoelastin that is a primary step for the in vivo polymerisation process of the elastin biosynthesis. Pressure may have a significant impact on the mechanism of elastin formation and its physico-biochemical characteristics in mammalian tissue living at deep ocean (i.e. high pressure) compared with creatures living at ambient pressure.

α-elastin was used to determine the effect of pressure on its temperature dependant molecular aggregation behaviour. α -elastin is soluble in water at low temperatures in the same manner as tropoelastin. The in vitro molecular aggregation process of α -elastin is equivalent to the molecular self-assembly process of biogenic tropoelastin in extracellular space of the vascular smooth muscle cells or fibroblast cells.

Analytical techniques such as UV spectroscopy and Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) were used to monitor the molecular aggregation of α -elastin at various temperatures and pressures. The effect of pressure on secondary structure of α -elastin was determined using Circular Dichorism (CD) technique.