Extraction, purification and characterisation of precursor proteins found in Pugilina cochlidium egg capsules

• Main Author: Tay, Eugene Ziquan
• Other Authors: School of Materials Science and Engineering
• Format: Final Year Project
• Language: English
• Published: 2012
• Subjects: DRNTU::Engineering::Materials::Biomaterials
• Online Access: http://hdl.handle.net/10356/48717
• Institution: Nanyang Technological University

It is sometimes most wonderful to know that nature holds many key clues and even solutions to engineering problems. Both a humble and incredible source of inspiration for scientists, it is a privilege to actually study nature and extract a wide spectrum of lessons from its amazing beauty, size, order and originality. The animal of interest in this study is the whelk snail Pugilina cochlidium, which produces a string of egg capsules to protect the young embryos. These egg capsule materials are made up of a bioelastomeric membrane that is resilient, and possesses unique self-healing and shock-absorbing properties. Mimics of this material could have potential uses in tissue engineering applications. The aim of this project was to extract, purify and characterize the precursor proteins of the egg capsule material. Purification by RP-HPLC was conducted, and one of the precursor proteins, PC-ECP 1, was successfully purified, as verified by SDS-PAGE. MALDI-TOF analysis determined the molecular weight of PC-ECP 1 to be 47.5 kDa. For characterization, samples of PC-ECP 1 were subjected to CD measurements, and data tabulated suggest the presence of 37.4 % α-helix and 15.6 % β-sheets in PC-ECP 1 under the conditions tested. The egg capsule material was also subjected to polarized light microscopy, and birefringence for the bulk material was calculated to be around 0.016. A comparison of the amino acid composition between the nidamental gland and the egg capsule was also executed, and a significant drop in percentage of lysine was noted. This suggests that lysine residues may be possibly involved in the sclereotising process that takes place during the egg capsule maturation.