iGem Groningen 2018



The IGEM team Groningen has invested a lot of effort into developing sophisticated models that simulates all parts of our project. In our quest for producing styrene from the polysaccharide cellulose, the first step is to get our enzymes to the place they need to go; cellulose. As the cellulose binding domain of our mini-cellulosome is responsible for this task, we characterized its cellulose binding properties by creating a cutting edge coarse grained molecular dynamics simulation and running it on our 6652 core supercomputer cluster peregrine. The simulation shows the cellulose binding domain as an affinity for cellulose several orders of magnitude higher than the enzymes alone and draw novel insights from this. However by restraining the enzymes together in a scaffold protein, the added rigidity might prove detrimental to enzyme activity. We used an advanced mathematical model to work out the complex system of differential equations that describe this restrained situation, and compared the results to the solubilized enzymes. Luckily, the model shows that restraining the enzymes only impacts their performance negligibly. Finally, we once more harnessed the supercomputing power at our disposal to simulate our synthetic styrene production pathway in the metabolism of S. cerevisiae using a flux based model. We confirmed that yeast is indeed capable of simultaneous growth and high theoretical styrene production. Most strikingly however, we discovered several important metabolic engineering targets, some of which are corroborated by empirical evidence, while others are entirely novel discoveries. Overall all our models have provided us with key insights to aid us in reaching our goal: a sustainable future.

Proximity by affinity

Our cutting edge molecular dynamics simulation uses the in-house developed MARTINI coarse grained force field to effectively model the thermodynamic properties of a reductionist view of our system.

Cellulose degradation

We were able to model the kinetic behaviour of a reduced enzyme scaffold. This system was described by a system of differential equations that describe the behaviour of the enzyme complex.

Optimizing styrene production

By using flux based analysis, the complex network of reactions in the metabolism of S. cerevisiae could be modeled. We used this approach to simulate styrene production and to find metabolic engineering targets.