Journal of the American Chemical Society
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phase formed by the micellar aggregate or by the monolayer.
Such an effect is not present in 1·Zn(II)2/-CD and 2·Zn(II)2.
Indeed, KM values in the low mM range are typical for dinu-
clear Zn(II) complexes.8b The greater affinity for the sub-
strate of 1·Zn(II)2/-CD with respect to 2·Zn(II)2 can be again
ascribed to the greater positive charge.
Bowden, A. Understanding allosteric and cooperative interactions in
enzymes. Febs Journal 2014, 281, 621-632.
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5
6
7
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(2) Goodey, N. M.; Benkovic, S. J. Allosteric regulation and cataly-
sis emerge via a common route. Nat. Chem. Biol. 2008, 4, 474-482.
(3) Traut, T. W. Dissociation of enzyme oligomers – A mechanism
allosteric regulation. Crit. Rev. Biochem. Mol. Biol. 1994, 29, 125-163.
(4) a) Raynal, M.; Ballester, P.; Vidal-Ferran, A.; van Leeuwen, P.
Supramolecular catalysis. Part 2: artificial enzyme mimics. Chem.
Soc. Rev. 2014, 43, 1734-1787; b) Wiester, M. J.; Ulmann, P. A.; Mirkin,
C. A. Enzyme Mimics Based Upon Supramolecular Coordination
Chemistry. Angew. Chem.-Int. Edit. 2011, 50, 114-137; c) Takebayashi,
S.; Shinkai, S.; Ikeda, M.; Takeuchi, M. Metal ion induced allosteric
transition in the catalytic activity of an artificial phosphodiesterase.
Org. Biomol. Chem. 2008, 6, 493-499.
(5) Centola, M.; Valero, J.; Famulok, M. Allosteric Control of Oxi-
dative Catalysis by a DNA Rotaxane Nanostructure. J. Am. Chem.
Soc. 2017, 139, 16044-16047.
(6) Marcos, V.; Stephens, A. J.; Jaramillo-Garcia, J.; Nussbaumer,
A. L.; Woltering, S. L.; Valero, A.; Lemonnier, J. F.; Vitorica-Yrezabal,
I. J.; Leigh, D. A. Allosteric initiation and regulation of catalysis with
a molecular knot. Science 2016, 352, 1555-1559.
(7) a) McGuirk, C. M.; Mendez-Arroyo, J.; d'Aquino, A. I.; Stern, C.
L.; Liu, Y.; Mirkin, C. A. A concerted two-prong approach to the in
situ allosteric regulation of bifunctional catalysis. Chemical Science
2016, 7, 6674-6683; b) McGuirk, C. M.; Mendez-Arroyo, J.; Lifschitz,
A. M.; Mirkin, C. A. Allosteric Regulation of Supramolecular Oli-
gomerization and Catalytic Activity via Coordination-Based Control
of Competitive Hydrogen-Bonding Events. J. Am. Chem. Soc. 2014,
136, 16594-16601.
(8) a) Diez-Castellnou, M.; Martinez, A.; Mancin, F.: Phosphate
Ester Hydrolysis: The Path From Mechanistic Investigation to the
Realization of Artificial Enzymes. Adv. Phys. Org. Chem. 2017, 51,
129-186. b) Mancin, F.; Tecilla, P. Zinc(II) complexes as hydrolytic
catalysts of phosphate diester cleavage: from model substrates to
nucleic acids. New J. Chem. 2007, 31, 800-817.
(9) Yu, Y.; Rebek, J. Reactions of Folded Molecules in Water. Acc.
Chem. Res. 2018, 51, 3031-3040.
(10) Note that the linear dependence obtained indicates the ab-
sence of relevant aggregation of the complex in the concentration
interval studies. See ref. 17.
(11) Diez-Castellnou, M.; Salassa, G.; Mancin, F.; Scrimin, P. The
Zn(II)-1,4,7-Trimethyl-1,4,7-Triazacyclononane Complex: A Mono-
metallic Catalyst Active in Two Protonation States. Front. Chem.
2019, 7, 469.
(12) Iranzo, O.; Elmer, T.; Richard, J. P.; Morrow, J. R. Cooperativity
between metal ions in the cleavage of phosphate diesters and RNA
by dinuclear Zn(II) catalysts. Inorg. Chem. 2003, 42, 7737-7746.
(13) Zaupa, G.; Mora, C.; Bonomi, R.; Prins, L. J.; Scrimin, P. Cata-
lytic Self-Assembled Monolayers on Au Nanoparticles: The Source of
Catalysis of a Transphosphorylation Reaction. Chem.-Eur. J. 2011, 17,
4879-4889.
(14)Note that the presence of pseudorotaxane-like inclusion com-
plexes cannot be ruled out on the basis of these experiments, but
they would be kinetically inactive as this structure would prevent the
two metal centers from getting close.
(15) a) Morrow, J. R.; Amyes, T. L.; Richard, J. P. Phosphate binding
energy and catalysis by small and large molecules. Acc. Chem. Res.
2008, 41, 539-548; b) Iranzo, O.; Kovalevsky, A. Y.; Morrow, J. R.;
Richard, J. P. Physical and kinetic analysis of the cooperative role of
metal ions in catalysis of phosphodiester cleavage by a dinuclear
Zn(II) complex. J. Am. Chem. Soc. 2003, 125, 1988-1993.
(16) Czescik, J.; Zamolo, S.; Darbre, T.; Mancin, F.; Scrimin, P. Fac-
tors Influencing the Activity of Nanozymes in the Cleavage of an
RNA Model Substrate. Molecules 2019, 24, 2814.
(17) Munana, P. S.; Ragazzon, G.; Dupont, J.; Ren, C. Z. J.; Prins, L.
J.; Chen, J. L. Y. Substrate-Induced Self-Assembly of Cooperative
Catalysts. Angew. Chem.-Int. Edit. 2018, 57, 16469-16474.
(18) Mohamed, M. F.; Neverov, A. A.; Brown, R. S. Investigation of
the Effect of Oxy Bridging Groups in Dinuclear Zn(II) Complexes
If the reactivity of the 1·Zn(II)2/-CD is due to the formation
of an inclusion complex, the catalytic activity of the system
might be regulated by a competitive host acting as antago-
nist. To test this hypothesis, we measured the rate of the
HPNP cleavage in the presence of 1·Zn(II)2/-CD and of in-
creasing concentrations of 1-adamantanecarboxylate, which
is water soluble and a well-known guest for cyclodextrins.
Results are reported in Figure 3B. As expected the reaction
rate decreased as the concentration of the adamantane de-
rivative increased. Both the sigmoidal shape of the inhibition
profile19 and the obtained value of the inhibitor binding con-
stant (Ki = 4.6 × 103 M-1)20 point against the possibility that
the inhibition observed could arise by the competitive bind-
ing of the carboxylate to the bimetallic center. This hypothe-
sis is further ruled out by the observation that addition of
sodium acetate at the same concentration of 1-adamantane-
carboxylate did not produce any effect on the reaction rate
(Figure 3B). In a last experiment, a reaction was started with
only 1·Zn(II)2 and HPNP in a cell. Subsequently, -CD (1
equivalent), 1-adamantanecarboxylate (2 equivalents) and
again 1·Zn(II)2 (1 equivalent) were added after fixed time in-
tervals. This sequence of additions produced the turning on,
off and on of the reactivity, as expected on the basis of the
proposed mechanism.
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This study describes the first example of the activation of a
catalyst by its inclusion into the cavity of a supramolecular
host of comparable size. The mechanism proposed mimics
the activation of catalytic sites by protein-protein associa-
tion. In addition, it offers wide possibilities for the realization
of complex chemical systems, where the reactivity is con-
trolled by the balance of different components.
Synthesis and characterization of 1, and additional kinetic
experiments. This material is available free of charge via the
fabrizio.mancin@unopd.it, paolo.scrimin@unipsd.it
The authors declare no competing financial interests.
This research was funded by the EU, Marie Curie program
MSCA-ITN-2016, project MMBio (grant 721613).
(1) a) Ricard, J.; Cornishbowden, A. Cooperative and allosteric en-
zymes - 20 years on. Eur. J. Biochem. 1987, 166, 255-272; b) Cornish-
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