Difference between revisions of "Part:BBa K3724011"

Revision as of 23:43, 20 October 2021

Outer Membrane Porin OprF

Two extracellular electron transfer pathways have been identified in the reduction of graphene oxide (GO) by Shewanella oneidensis MR-1. These are indirect electron transfer, mediated by secreted electron shuttles, and direct extracellular electron transfer (DET) which involves direct contact with the extracellular material. To increase the number of electron shuttles exiting the cell into the extracellular space. Increased extracellular electron donors should increase the reduction rate by Shewanella oneidensis MR-1

Usage and Biology

Shewanella oneidensis MR-1 are gram-negative bacteria at the center of studies of microbial reduction due to their ability to transfer electrons extracellularly to reduce materials such as graphene oxide (GO)[1]. Such characteristics have made S. oneidensis MR-1 an organism of interest in microbial fuel cells for bioelectricity generation and potential applications in bioremediation[2]. Two extracellular electron transfer pathways have been identified in the reduction of GO by Shewanella oneidensis MR-1. These are indirect electron transfer, mediated by secreted electron shuttles, and direct extracellular electron transfer (DET) which involves direct contact with the extracellular material[3]. The oprF gene found in Pseudomonas aeruginosa encodes the outer membrane porin F which is a nonspecific porin that allows for the diffusion of various molecules across the outer membrane.[4] The expression of this porin in S. oneidensis MR-1 has been seen to increase the electron shuttles, flavins, in the extracellular space leading to an increase in power generation in microbial fuel cells.[3] Another study has shown that this expression results in increased biofilm formation due to increased membrane permeability which ultimately increased bioelectricity generation[5]. oprF is seen to play a role in both the indirect and direct pathways for electron transfer in S. oneidensis MR-1 through the increase in electron shuttles and the increase in contact with the terminal electron acceptor via increased biofilm production. It was thought that the expression of oprF in S. oneidensis MR-1 would lead to an increase in flavins and other electron shuttles in the extracellular space as well as potentially increase biofilm production. This in turn would result in an increased rate of reduction of GO.

We therefore, synthesized the ydeH gene, optimized for S. oneidensis MR-1 , and inserted it into the kanamycin resistant vector pcD8 under the control of an IPTG-inducible promoter (Keitz lab, University of Texas Austin)[6].

Sequence and Features

References

[1] Wang, G.; Qian, F.; Saltikov, C. W.; Jiao, Y.; Li, Y. Microbial Reduction of Graphene Oxide by Shewanella. Nano Research 2011, 4, 563–570.
[2] Schwalb, C.; Chapman, S. K.; Reid, G. A. The Tetraheme Cytochrome Cyma Is Required for Anaerobic Respiration with Dimethyl Sulfoxide and Nitrite in Shewanella Oneidensis. Biochemistry 2003, 42, 9491–9497.
[3] Lin, T.; Ding, W.; Sun, L.; Wang, L.; Liu, C.-G.; Song, H. Engineered Shewanella Oneidensis-Reduced Graphene Oxide Biohybrid with Enhanced Biosynthesis and Transport of Flavins Enabled a Highest Bioelectricity Output in Microbial Fuel Cells.

[4] Sugawara, E.; Nestorovich, E. M.; Bezrukov, S. M.; Nikaido, H. Pseudomonas Aeruginosa Porin Oprf Exists in Two Different Conformations. Journal of Biological Chemistry 2006, 281, 16220–16229.
[5] Lin, T.; Bai, X.; Hu, Y.; Li, B.; Yuan, Y. J.; Song, H.; Yang, Y.; Wang, J. Synthetic Saccharomyces Cerevisiae ‐ Shewanella Oneidensis Consortium Enables Glucose‐Fed High‐Performance Microbial Fuel Cell. AIChE Journal 2016, 63, 1830–1838.
[6] Dundas, C. M.; Walker, D. J. F.; Keitz, B. K. Tuning Extracellular Electron Transfer by Shewanella Oneidensis Using Transcriptional Logic Gates. ACS Synthetic Biology 2020, 9, 2301–2315.