Team:TJUSLS China

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Abstract

Our project helps to increase the possibility of achieving the biodegradation of highly crystallized PET by enhancing the thermostability of PETase, contributing to solving environmental and health problems caused by the abuse of PET.

Issues of highly crystallized PET

The excellent properties of highly crystallized PET make it difficult to degrade in nature. It is regarded as a material that causes great damage and harm to the soil, ocean and human body.

Our Solution

——To improve the thermal stability modification of PETase

Most of the existing work focuses on the transformation of its degradation activity and improve the activity, with little attention paid to the thermal stability of PETase. However, in practical applications and through the study of the homologous enzymes of PETase, such as LCC, we found that thermal stability largely restricted PETase to play its due role. Therefore, we try to improve the thermal stability modification of PETase.

Methods

Through the study of the homologous enzymes of PETase, we discovered the possibility of improving the thermal stability of the protein through site mutations and thereby enhancing the activity of the protein. By observing the structure of PETase from different directions, we modified the structure and introduced benign mutations. At the same time, we use FoldX to evaluate the DDG value, use PyMOL to observe the structure, and finally select the best multi-point mutation combination, which has significantly improvement on thermal stability.

Model

We developed two models to predict the thermostability of a target protein. Our mathematical model of ΔΔG and Tm value is a bridge built between simulations and experimental results and our molecular dynamics simulation achieves high prediction of changes of dynamic stability of proteins at a certain high temperature.

Human Practices

From online to offline, investigation, communication, and sharing connect our work with the world. HP is an important part of our project and is the guiding ideology for our project improvement. We not only appeal to people for the environmental problems caused by PET, but also spread the charm of synthetic biology.