2OKW

A non-invasive GFP-based biosensor for mercury ions

Summary for 2OKW

• Entry DOI: 10.2210/pdb2okw/pdb
• Related: 2OKY
• Descriptor: Green fluorescent protein (2 entities in total)
• Functional Keywords: mercury, biosensor, luminescent protein
• Biological source: Aequorea victoria
• Total number of polymer chains: 6
• Total formula weight: 161390.19

Authors

Chapleau, R.R.,Blomberg, R.,Ford, P.C.,Sagermann, M. (deposition date: 2007-01-17, release date: 2007-12-04, Last modification date: 2024-10-16)

Primary citation

Chapleau, R.R.,Blomberg, R.,Ford, P.C.,Sagermann, M.
Design of a highly specific and noninvasive biosensor suitable for real-time in vivo imaging of mercury (II) uptake.
Protein Sci., 17:614-622, 2008

PubMed Abstract: Mercury is a ubiquitous pollutant that when absorbed is extremely toxic to a wide variety of biochemical processes. Mercury (II) is a strong, "invisible" poison that is rapidly absorbed by tissues of the intestinal tract, kidneys, and liver upon ingestion. In this study, a novel fluorescence-based biosensor is presented that allows for the direct monitoring of the uptake and distribution of the metal under noninvasive in vivo conditions. With the introduction of a cysteine residue at position 205, located in close proximity to the chromophore, the green fluorescent protein (GFP) from Aequorea victoria was converted into a highly specific biosensor for this metal ion. The mutant protein exhibits a dramatic absorbance and fluorescence change upon mercuration at neutral pH. Absorbance and fluorescence properties with respect to the metal concentration exhibit sigmoidal binding behavior with a detection limit in the low nanomolar range. Time-resolved binding studies indicate rapid subsecond binding of the metal to the protein. The crystal structures obtained of mutant eGFP205C indicate a possible access route of the metal into the core of the protein. To our knowledge, this engineered protein is a first example of a biosensor that allows for noninvasive and real-time imaging of mercury uptake in a living cell. A major advantage is that its expression can be genetically controlled in many organisms to enable unprecedented studies of tissue specific mercury uptake.

PubMed: 18305194
DOI: 10.1110/ps.073358908

Experimental method

X-RAY DIFFRACTION (1.9 Å)