Page 115 - Read Online

Zhong et al. Chem Synth 2023;3:27 https://dx.doi.org/10.20517/cs.2023.15 Page 9 of 25

2+
Figure 5. Schematic illustration of gated dissipative networks operated by the Pb -ion-dependent DNAzyme. This figure is quoted with
[116]
permission from Wang et al. .
network to decide which transient signal can be reported. The network includes a duplex AB, where A is a
Pb -ion-dependent DNAzyme sequence, and its catalytic activity is blocked by B; strands C, D, and E are
2+
modified with Cy5, BHQ2, and Cy3 and act as reporter units for generating output signals. After adding
ribonuclease-containing fuel strand T, duplex AB is displaced to form duplex AT and release single-strand
B, which can activate the reporter units by forming duplex structures BCD and BDE. The spatial proximity
between Cy5 and BHQ2 in BCD and between Cy3 and BHQ2 in BDE leads to the quenching of Cy5 and
Cy3 as competitive output signals due to the two reporter units sharing common strand D. Due to the
release of blocker B from AB, the catalytic activity of DNAzyme A is transiently turned on for the cleavage
of fuel strand T, leading to the backward strand displacement reaction. Then reporter units BCD and BDE
are dissociated, and duplex AB is re-formed, displaying an integrated dissipative reaction cycle. The gated
operation of DNAzyme-guided dissipative networks is achieved by controlling the signal pathway between
two competitive signal reporter units. Upon the addition of fuel strand T, and in the absence of the
inhibitors I or I , two signal reporter units, BCD and BDE, are transiently activated; however, in the
2
1
presence of I , the transient gated activation of signal reporter unit BDE occurs, while in the presence of
1
inhibitor I , the temporary gated operation of signal reporter unit BCD proceeds.
2