Team:Imperial College London/Drylab/Protein Production

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Protein Production

Based on the Genetic circuit, a LacI-IPTG inducible promoter is responsible for kickstarting the production of the drug.

  • In the absence of IPTG, LacI represses the production of the drug (Cellulase or PAH)
  • When IPTG is introduced, the LacI repressing pathway is “de-repressed”, and some output protein is produced.
II09 NoIPTG yesIPTG.jpg


Contents

Our goals

The modelling aims to provide an overview and better understanding of the M1 system’s function by:

  • Characterizing the system.
  • Modeling to account for several factors that may reduce/hinder the production of the protein drug such as:
    • Lac promoter leakiness
    • IPTG toxicity
    • Stability of output protein


This module is an integral part of the design, as large-scale commercialization of the drug of interest depends on finding the optimal conditions for protein production.

  about the model assumptions and predictions!


The System

There are 6 differential equations that describe the behaviour of this system.
  about the equations and what they mean!


Summary of simulation results

  • When we introduce IPTG into the system, it temporarily removes LacI from the system. Hence, during this period of time, we produce the drug of interest.
  • When the effects of IPTG wear off, the system returns to equilibrium.
  • The more IPTG we add in, the higher the amount of output protein.

II09 SIm main prot.jpg

  about the simulations!


Conclusions

NOTE: These will be better understood once the reader has gone through the details ("Learn More").

  • The greater the strength of the Lac promoter, the greater the repressive action of LacI prior IPTG induction.
  • The greater the Lac promoter leakiness (kleak) the greater the basal amount of expression of protein of interest, prior IPTG induction.
  • The greater the amount of IPTG introduced, the greater the size of the bump in production of protein of interest.
  • Here we assumed that the range of IPTG we have introduced is non-toxic for our cells. Growth curves will tell us whether IPTG does limit cell growth at the ranges we are interested in.

References

[1]Steven H. Strogatz (1994). Nonlinear dynamics and chaos: with applications to physics, biology chemistry and engineering. Addison Wesley. ISBN 0-201-54344-3
[2]3.Kuhlman T, Zhang Z, Saier MH Jr, & Hwa T (2007) Combinatorial transcriptional control of the lactose operon of Escherichia coli. - PNAS 104 (14) 6043-6048


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