Difference between revisions of "Part:BBa K3596055"

Revision as of 01:26, 28 October 2020

PpdD Signal+Pilin gene

BIOT is a basic design for the expression of Geobacter sulfurreducens' pilin-based electrically conductive protein nanowires (e-PNs)^[1]. This part codes for the monomer of Geobacter sulfurreducens' pilin-based electrically conductive protein nanowires(e-PNs)(figure 4A) along with the E.coli PpdD signal sequence to facilitate the construction of e-PNs at N terminal.

Characterization

The e-PN can be successfully expressed by express this part under the control of pTac with typeIV pilin assembly system(figure 1)

Figure 1: The Genetic circuit of BIOT

Then we followed the protocol to purify the target protein(figure 2), gaining protein with a concentration ranging from 200 to 400 μg/ml(figure 3).

Figure 2: The procedures for BIOT nanowires purification.

Figure 3: The Protein Concentration of BIOT purification.

Western Blot was used to confirm the product protein as our targeting one, and the result showed it clearly (figure 4).

Figure 6: The Structure of e-PN monomer protein(A) and Western blot to verify the expression of BIOT monomers;(B).

We made a protein film following the instructions from the paper we researched(figure 5).^[2]

Figure 5: BIOT membrane on the transparent membrane.

Then we successfully built up the basic module of BIOT (figure 6) using this protein film.The gold positive electrode at the bottom is larger so that the e-PNs can be positioned on it. And the tiny circular carbon piece works as a negative electrode on the top.

Figure 6: BIOT Assembly and Measurement

We eventually succeeded in producing stable voltage at about 0.35V with a current of 500nA or so (under 60% relative humidity)(figure 7 A,B).Additionally, to find the optimum relative humidity for the battery to function, we did the measurement with different relative humidities. The optimum RH was roughly at 40-50%, where the voltage rises to about 0.42V (figure 7C).

Figure 7: The Key parameters of BIOT basic module.
A, The voltage of BIOT; B, the current of BIOT; C, Voltage of BIOT under different relative humidities.

References

[1] Ueki, Toshiyuki, et al. An Escherichia Coli Chassis for Production of Electrically Conductive Protein Nanowires. ACS Synthetic Biology, vol.9, no.3, 3 Mar.2020, pp.647–654.

[2] Liu, Xiaomeng, et al.. Power Generation from Ambient Humidity Using Protein Nanowires. Nature, vol.578, no.7796, Feb.2020, pp.550–554.

Sequence and Features