Difference between revisions of "Part:BBa K5236004"

Latest revision as of 12:51, 2 October 2024

IsPETase H104W

IsPETase is friendly to enviorment and energy-saving to chemical recycling of PET. However, the temperature for it to react is even lower than glass transition temperature of PET.This basic part encodes mutated IsPETase H104W and constructed in Escherichia coli.

Usage and Biology

To generate mutated variants, we have trained a Transformer AI model. This model predicts the top 10 potential mutation sites, which are likely to have significant impacts on the enzyme's structure and function. Next, we analyzed the top 10 potential sites via Meta's ESM-1b model to eliminate the silent mutations, which involve changes in nucleotides that do not altering the corresponding amino acids. This ensures that the mutations result in changes in the enzyme's structure and thereby its function. For further information, please check the model page on our wiki. https://2024.igem.wiki/basis-china/model

The IsPETase H104W sequence is expressed in E.coli BL21(DE3) using the pET28a vector. The pET-28a is a classical plasmid vector used for protein expression in E.coli. This vector contains the T7 promoter, the lac operator, a ribosome binding site, the 6xHis sequence, and the T7 terminator. The T7 promoter is a strong promoter recognizable by T7 RNA polymerase, used to regulate gene expression of recombinant proteins. The lac operator can be activated by IPTG and used to control gene expression. The 6xHis sequence encodes for a tag that facilitates protein purification. Asides from the features included in the plasmid backbone, we added a signal peptide sequence — pELB — before the IsPETase H104W sequence, which is inserted between the promoter and terminator.

By conducting colony PCR, we are able to test if our parts have been transformed into chassis successfully. The following result of electrophoresis proves that we’ve inserted genes into chassis since the sequence containing our mutated genes has a total of 891 base pairs and the results are in the right location.

After proving that our genes existed in chassis, we need to test if the bacteria can survive as usual with our genes. Thus, we’ve coated the bacteria on nutritional petri dish. And after a night, E. coli grew over the plate our plate, justifying that E. coli can survive with the gene of our part.

We tested whether the bacteria could translate for our protein, and we examined whether our mutated enzyme is more efficient. For this section, we analyzed two results as well. First, the dynamic curve of our enzyme shows its high efficiency in degrading rate. Second, the electrophoresis result of our protein proves that our enzyme can be successfully coded by the parts we designed.

Reference

Brott, S., Pfaff, L., Schuricht, J., Schwarz, J.-N., Böttcher, D., Badenhorst, C. P. S., Wei, R., & Bornscheuer, U. T. (2021, November 29). Engineering and evaluation of thermostable isPETASE variants for PET degradation. Engineering in life sciences. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8961046/

Sequence and Features