Welcome to Drylab
Drylab is one of the three core teams of Westview iGEM, responsible for the computational aspect of the research project. While Wetlab has been responsible for engineering FastPETase into Ideonella sakaiensis, the Drylab group is responsible for simulating and modeling the behavior of FastPETase to determine the stability of the FastPETase enzyme over time. This year, the Drylab chose to focus on comparing different variants of the PETase enzyme, including the one that Wetlab implemented in the 2022-2023 season (regular PETase), to determine which PETase variant would be optimal for implementation.
What's in a PETase?
PETases are a group of enzymes that can catalyze the hydrolysis of polyethylene terephthalate (PET) into its monomer constituent, MHET. In other words, PETase enzymes can break down PET plastics! In particular, the PETase enzymes have a key component that allow them to break down PET molecules: its catalytic triad of amino acids. Serine 160, Histidine 237, and Aspartate 206 work together to allow PETase to “attack” the PET molecule (Hence the three orbs on petACE’s sword).
However, naturally-occuring PETases are too unstable and inactive to be used commercially as a solution to the plastic crisis. Particularly, PETase as it exists in nature is not very thermostable. Many scientists have mutated PETase, in hopes of making it more thermostable, more active, and more structurally sound. In fact, HotPETase is a PETase variant created from directed evolution, and FastPETase is a PETase variant designed with the help of A.I.
OG PETase
First is the original, or OG PETase. OG PETase was studied in Westview’s 2022-2023 year iGEM project.OG PETase was discovered from the organism Ideonella Sakaiensis in 2016 by Kyoto Institute of Technology researchers at a PET recycling site. The term "OG" has no scientific significance-- it stands for "OriGinal" to represent the fact that Wetlab used this enzyme last year.
HotPETase
Second is a PETase formed through directed evolution, called HotPETase. A high-throughput computing method called “directed evolution” was used to evaluate 13,000+ PETase variants and create 21 mutations that increased the thermostability of PETase so it was able to operate around the glass transition temperature. 2 disulfide bridges were rationally designed and another 16 were inserted with locations given from the directed evolution. Disulfide bridges are known to increase structural stability of an enzyme’s tertiary structure. The result of the mutations was a more thermostable protein that operated under more suitable temperatures.
Fast PETase
And last, but not least, is FastPETase, a PETase variant that was created using a machine-learning (ML) algorithm with only 5 mutations from the wild type of PETase. This is the PETase that Wetlab is using for this year. “FAST” stands for functional, active, stable, (and) tolerant PETase. Indeed, FastPETase is able to break down PET into its monomers at a much faster rate than wild-type PETases, and at a wider range of temperature than wild-type PETases, which have an optimal temperature of 40 degrees Celsius. FastPETase functions from 30-60 degrees Celsius, but functions optimally at 50 degrees Celsius.
How to Navigate Drylab
Due to the nature of the wiki implementation, there might be some confusion in navigation between pages. Sequentially, the MODELS tab under the AWARDS section is the 2nd part, and the RESULTS AND ANALYSIS under the Drylab Tab is the last and final section.
