Part:BBa_K3731002
vgb
The vgb can produce HGB so that we can increase bacteria’s capacity of carrying oxygen, which is beneficial to the growth of bacteria.
Sequence and Features
- 10COMPATIBLE WITH RFC[10]
- 12COMPATIBLE WITH RFC[12]
- 21COMPATIBLE WITH RFC[21]
- 23COMPATIBLE WITH RFC[23]
- 25COMPATIBLE WITH RFC[25]
- 1000COMPATIBLE WITH RFC[1000]
iGEM2021_Nanjing-China Experiment
Group: Nanjing-China 2021
Author: Hao Yin
Bacterial hemoglobin (VtHb) is produced by the gram-negative bacterium, Vitreoscilla , in large quantity in response to hypoxic environmental conditions. The vgb gene coding for VtHb has been cloned in E. coli where it is expressed strongly by its natural promoter. The expression of the vgb gene in Vitreoscilla is transcriptionally regulated by oxygen. Vitreoscillu hemoglobin (VHb) is expressed at elevated levels in Vitreoscillu under oxygen-limited cultivation conditions.
To evaluate the role of oxygen and the mechanism by which it regulates VtHb production, expression of the vgb gene in E. coli in response to different oxygen levels were studied. E. coli JM83 with recombinant plasmid pUC8:16 was grown at 20% and 5% oxygen and the amount of vgb specific RNA transcript was measured. Both VtHb mRNA and the protein itself were significantly more abundant in cells grown at 5% oxygen. Only a small amount of vgb specific transcript was detectable in cells grown at atmospheric oxygen (Fig. 1). The growth responses of cells containing plasmid pUC8 with and without the vgb gene under the above conditions were compared: the growth rate of cells with plasmid pUC8 alone was lower than with cells containing pUC8:16 with vgb present (Fig 1). These results confirm that the synthesis of hemoglobin in E. coli is regulated in response to oxygen as it is in Vitreoscilla and that its presence is beneficial for these cells when oxygen is limited.
In view of this, we take advantage of vgb to help bacteria to survive unfavorable environment, thus increasing the productivity of polyP.
Reference:
Kallio, P. T.; Kim, D.; Tsai, P. S.; Bailey, J. E. Intracellular expression of Vitreoscilla hemoglobin alters Escherichia coli energy metabolism under oxygen-limited conditions. The FEBS Journal 1994, 219 (1-2), 201-208.
Kanak L. Dikshit, Rajendra P. Dikshit, Dale A. Webster, Study of Vitreoscilla globin(vgb) gene expression and promoter activity in E. Coli through transcriptional fusion , Nucleic Acids Research, Volume 18, Issue 14, 25 July 1990, Pages 4149–4155.
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