posted on 2017-06-06, 00:00authored byXin Shang, Nanxi Wang, Ronald Cerny, Wei Niu, Jiantao Guo
We demonstrated a
general protection–deprotection strategy
for the design of fluorescent protein biosensors through the construction
of a turn-on Hg2+ sensor. A combination of fluorescent
protein engineering and unnatural amino acid mutagenesis was used.
Unlike previously reported fluorescent protein-based Hg2+ sensors that relied on the binding of Hg2+ to the sulfhydryl
group of cysteine residues, a well-established chemical reaction,
oxymercuration, was transformed into biological format and incorporated
into our sensor design. This novel Hg2+ sensor displayed
good sensitivity and selectivity both in vitro and in live bacterial
cells. Over 60-fold change in fluorescence signal output was observed
in the presence of 10 μM Hg2+, while such a change
was undetectable when nine other metal ions were tested. This new
design strategy could expand the repertoire of fluorescent protein-based
biosensors for the detection of small-molecule analytes.