Difference between revisions of "Part:BBa K533008:Design"

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When a E. coli strain lack all the chemoreceptors express a certain receptor in the plasmid, it will be conferred the chemotaxis towards the ligand. Interestingly, sensitivity of chemotaxis does not increase as the expression level of the receptor increases; on the contrary, low expression level of the receptor is essential to sensitive chemotaxis. It can be inferred that high level of receptors caused an internal noise, which interfered with normal chemotaxis.
 
When a E. coli strain lack all the chemoreceptors express a certain receptor in the plasmid, it will be conferred the chemotaxis towards the ligand. Interestingly, sensitivity of chemotaxis does not increase as the expression level of the receptor increases; on the contrary, low expression level of the receptor is essential to sensitive chemotaxis. It can be inferred that high level of receptors caused an internal noise, which interfered with normal chemotaxis.
  
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This sequence was cloned from plasmid PD12-TarPA4 (kind gift from Prof. Mark Goulian, U Penn). An accidental ligation occured, causing the receptor coding sequence to insert into lacI sequence. Furthermore,some of the sequence in lacI can serve as a weak promoter, driving extremely low level expression of the receptor.
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This receptor is specific for phenylacetic acid, or PAA for short. Since PAA is not naturally existing, it can lower the background and facilitate better chemotaxis. As the experiments in Goulian's lab demonstrated, the maximum concentration of the chemoattractant in soft agar is 10mM. A concentration higher than that will saturate the receptor and hinder chemotaxis.
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This receptor is specific for phenylacetic acid, or PAA for short. As the experiments in Goulian's lab demonstrated, the maximum concentration of the chemoattractant is 10mM. A concentration higher than that will saturate the receptor and hinder chemotaxis.
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===Source===
 
===Source===

Latest revision as of 09:20, 5 October 2011

PAA receptor


Assembly Compatibility:
  • 10
    COMPATIBLE WITH RFC[10]
  • 12
    INCOMPATIBLE WITH RFC[12]
    Unknown
  • 21
    COMPATIBLE WITH RFC[21]
  • 23
    COMPATIBLE WITH RFC[23]
  • 25
    INCOMPATIBLE WITH RFC[25]
    Illegal AgeI site found at 1282
  • 1000
    COMPATIBLE WITH RFC[1000]


Design Notes

When a E. coli strain lack all the chemoreceptors express a certain receptor in the plasmid, it will be conferred the chemotaxis towards the ligand. Interestingly, sensitivity of chemotaxis does not increase as the expression level of the receptor increases; on the contrary, low expression level of the receptor is essential to sensitive chemotaxis. It can be inferred that high level of receptors caused an internal noise, which interfered with normal chemotaxis.

This receptor is specific for phenylacetic acid, or PAA for short. Since PAA is not naturally existing, it can lower the background and facilitate better chemotaxis. As the experiments in Goulian's lab demonstrated, the maximum concentration of the chemoattractant in soft agar is 10mM. A concentration higher than that will saturate the receptor and hinder chemotaxis.

Source

This is a kind gift from Dr. Goulian.


References

Goldberg, S. D., P. Derr, et al. (2009). "Engineered single- and multi-cell chemotaxis pathways in E. coli." Mol Syst Biol 5: 283.