Difference between revisions of "Part:BBa K2328027"

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smURFP I + Linker A + RBS I + HO-1 I

Sequence and Features

Usage

It’s a co-expression system. smURFP (small ultra-red FP) is an important part in our group. It is desirable for our in vivo imaging because with it molecule less light is scattered, absorbed, or re-emitted by endogenous biomolecules compared with cyan, green, yellow and orange FPs. smURFP can covalently attaches a biliverdin (BV) chromophore without a lyase, and has 642/670 nm excitation - emission peaks, a large extinction coefficient and quantum yield, and photostability comparable to that of eGFP. HO-1 is the gene of the precursor of biliverdin. HO-1 can use the materials of the E.coil to produce biliverdin. So we want to construct a plasmid which can both express the smURFP gene and HO1 gene. Through this contruction, we can achieve the co-expression in the E.coil. Both the smURFP and biliverdin are produced by E.coil, so they can connect directly within the E.coil to produce fluorescence under the wavelength of 642nm without to add BV additionally. Besides, smURFP I and HO-1 I are both the codon-optimized version for Escherichia coli.

Biology

In order to produce fluoresce, smURFP must be combined with biliverdin (BV) .So one of our method is co-expression. Because the HO-1 needs to use oxygen to produce BV, it is adoptable in E.coil which is a kind of facultative anaerobic bacteria. And the HO-1 gene is from the Block Library. Through this contruction, we can achieve the co-expression in the E.coil. Both the smURFP and biliverdin are produced by E.coil, so they can connect directly within the E.coil to produce fluorescence under the wavelength of 642 nm.

Reference

[1] Rodriguez EA,Tran GN , Gross LA, et al. A far-red fluorescent protein evolved from a cyanobacterial phycobiliprotein .[J].NATURE METHODS,2016:763-769. [2] Dong Chen, Jason D Brown, Yukie Kawasaki, Jerry Bommer and Jon Y Takemoto. Scalable production of biliverdin IXα by Escherichia coli. [J].BMC Biotechnology, 2012.

Results

Co-expression in E.coli BL21

Fluorescence detection with Microplate Reader

Plasmid pET28b with smURFP and HO-1 gene were transformed into E. coli BL-21. We used this induced bacteria to confirm the fluorescence and data showed a relatively high value, as shown in table 1.

Table 1. Result of Microplate Reader in the black 96-well plate. Tube 1 and 2 are experimental group, and tube 3 is the control group.

Fluorescence imaging with FCFM

Then laser confocal microscopy was use to observe these bacteria, activate light of 640nm was used, as shown in Figure 2.

Figure 2. The result after induction, the upper one is the control group, and the inferior one is the experimental group.