Cuero. R., Mckay. D. 2013. “Induction and Construct UV Protective Yeast Plasmid ”.
Journal of Biotechnology (Elsevier). In Press. http://www.sciencedirect.com
Cuero, R. 2013. DNA sensors for predicting diabetes: A synthetic biology approach. International Conference on Integrative Biology Summit, Las Vegas, August 5-7, 2013. See more:http://www.omicsgroup.com
Cuero, R. 2012. DNA Sensor for early detection of diabetes. World Congress of molecular medicine - Emerging Technology. Guangzhou, China. December 1 – 4, 2012.
Cuero. R. et al. 2012. “Constructed molecular sensor to enhance metal detection by bacterial ribosomal switch-ion channel protein interaction”. Journal of Biotechnology (Elsevier).
Vol 158 (12012): 1-7
Molecular biosensors are useful tools that detect metal ions or other potentially toxic chemicals.
However, the efficiency of conventional sensors is limited in mixed metals substrates, which is
the common way they are found in nature. The use of biosensors constructed from genetically
modified living microbial systems has the potential of providing sensitive detection systems for
specific toxic targets. Consequently, our investigation was aimed at assembling different genetic
building blocks to produce a focused microbial biosensor with the ability to detect specific metals.
This objective was achieved by using a synthetic biology approach. Our genetic building blocks,
including a synchronized ribosomal switch–iron ion channel, along with sequences of promoters,
metal-binding proteins (Fe, Pb), ribosomal binding sites, yellow fluorescence reporter protein
(YFRP), and terminators, were constructed within the same biobrick in Escherichia coli. We used an rpoS ribosomal switch containing an aptamer, which responds to the specific metal ligands, in synchronization with an iron ion channel, TonB. This switch significantly stimulates translation, as expressed by higher fluorescence, number of colonies, and concentration of RNA in E. coli.
The positive results show the effectiveness of using genetically tailored synchronized ribosomal
switch–ion channels to construct microbial biosensors to detect specific metals, as tested in iron solutions.
Fig. 1. Graphic illustration of constructed plasmid showing the direction, placement and size of
genes within the pBSKII vector beginning with the T3 promoter, iron promoter, riboswitch rpoS,
ion channel, iron-binding protein, lead-binding protein, yellow fluorescent reporter protein (YFRP),
and the terminator sequence. Ampicillin resistance gene is included as a genetic marker and was used for screening colonies that had successfully been transformed with the plasmid.
Fig. 2. Graphic illustration of the ribosomal switch–ion channel synchronization. When bound to
the S1 regulatory protein, the rpoS riboswitch undergoes a change in tertiary structure, allowing
the ribosome to bind to the RBS and initiate translation of the downstream TonB ion channel.
The translated voltage-gated ion channel becomes embedded in the cellular membrane, allowing
bivalent cations to pass into the cell, becoming oxidized as they enter, aiding in the synthesis of
Fig. 3. Graphic illustration detailing the mechanics of the ribosomal switch–ion channel
synchronization. (A) The change in rpoS tertiary structure when bound to ligand metabolite
favoring iron (Fe2+) regulation. (B) Ribosomal switch favoring lead (Pb2+) regulation.
Cuero, R. et. al. 2011. Synchronization of Riboswitch-Ion Channels Proteins
for Detection of Specific Metals. SynBERC-NSF Meeting. Berkeley University.
"DNA Sensor for Detection of Chemical Contamination:
Use of SyntheticBiology. World Congress of DNA and Genome Day. Dalian,China.
Cuero. R. Biogenesis:Application of SyntheticBiology. Synthetic
Biology Symposium. SynBERC-NSF. Prairie View A&M University. 2010
Cuero R, et al. 2009. Metabolic Parts Network, as Sendor for Metals. Advances in Synthetic Biology. University of London. April 28 - April 29, 2009. London