Bioorthogonal Catalysis: A General Method To Evaluate
Metal-Catalyzed Reactions in Real Time in Living Systems Using a Cellular
Luciferase Reporter System
Hsiao-Tieh Hsu
Brian M. Trantow
Robert M. Waymouth
Paul A. Wender
10.1021/acs.bioconjchem.5b00469.s001
https://acs.figshare.com/articles/journal_contribution/Bioorthogonal_Catalysis_A_General_Method_To_Evaluate_Metal_Catalyzed_Reactions_in_Real_Time_in_Living_Systems_Using_a_Cellular_Luciferase_Reporter_System/2077969
The development of abiological catalysts
that can function in biological
systems is an emerging subject of importance with significant ramifications
in synthetic chemistry and the life sciences. Herein we report a biocompatible
ruthenium complex [Cp(MQA)Ru(C<sub>3</sub>H<sub>5</sub>)]<sup>+</sup>PF<sub>6</sub><sup>–</sup> <b>2</b> (Cp = cyclopentadienyl,
MQA = 4-methoxyquinoline-2-carboxylate) and a general analytical method
for evaluating its performance in real time based on a luciferase
reporter system amenable to high throughput screening in cells and
by extension to evaluation in luciferase transgenic animals. Precatalyst <b>2</b> activates alloc-protected aminoluciferin <b>4b</b>, a bioluminescence pro-probe, and releases the active luminophore,
aminoluciferin (<b>4a</b>), in the presence of luciferase-transfected
cells. The formation and enzymatic turnover of <b>4a</b>, an
overall process selected because it emulates pro-drug activation and
drug turnover by an intracellular target, is evaluated in real time
by photon counting as <b>4a</b> is converted by intracellular
luciferase to oxyaminoluciferin and light. Interestingly, while the
catalytic conversion (activation) of <b>4b</b> to <b>4a</b> in water produces multiple products, the presence of biological
nucleophiles such as thiols prevents byproduct formation and provides
almost exclusively luminophore <b>4a</b>. Our studies show that
precatalyst <b>2</b> activates <b>4b</b> extracellularly,
exhibits low toxicity at concentrations relevant to catalysis, and
is comparably effective in two different cell lines. This proof of
concept study shows that precatalyst <b>2</b> is a promising
lead for bioorthogonal catalytic activation of pro-probes and, by
analogy, similarly activatable pro-drugs. More generally, this study
provides an analytical method to measure abiological catalytic activation
of pro-probes and, by analogy with our earlier studies on pro-Taxol,
similarly activatable pro-drugs in real time using a coupled biological
catalyst that mediates a bioluminescent readout, providing tools for
the study of imaging signal amplification and of targeted therapy.
2016-02-17 00:00:00
MQA
4- methoxyquinoline -2-carboxylate
luciferase reporter system
Precatalyst 2 activates alloc-protected aminoluciferin 4 b
luminophore
PF
method
imaging signal amplification
precatalyst 2 activates 4 b extracellularly
formation
Cellular Luciferase Reporter System
analogy
presence
emulates pro-drug activation
intracellular
abiological
activatable pro-drugs
Cp
Evaluate Metal-Catalyzed Reactions
pro-probe