Structure-activity study of a sweet protein.

• Main Author: Huang, Xuhua.
• Other Authors: Liu Chuan Fa
• Format: Final Year Project
• Language: English
• Published: 2009
• Subjects: DRNTU::Science::Biological sciences::Genetics
• Online Access: http://hdl.handle.net/10356/18944
• Institution: Nanyang Technological University

Brazzein, isolated from the fruit of the wild African plant Pentadiplandra brazzeana Baillon, is one of the few sweet proteins discovered to date. Being one of the sweetest sweet protein with the highest water solubility, brazzein retains its sweetness for 2 hours at 98 oC. Increasing the heat stability or sweetness profile of the brazzein protein would result in its wider usage in the food industry, thus benefiting many on health issues such as obesity and diabetes. The synthetic wild type brazzein gene was first constructed, and used in the synthesis of a new brazzein variant called the cyclised brazzein in which the N-terminus of brazzein is directly linked to its C-terminus through a peptide bond. The circulisation technique is based on an intein-mediated protein ligation mechanism discovered by New England Biolabs, Inc.. The protein was RP-HPLC purified and its molecular weight was confirmed by MALDI-MS. Although the sweet profile of the cyclised brazzein does not look promising from preliminary studies, the protocol developed here could be referred upon in the further development of other cyclised analogs of brazzein.