Please cite this article in press as: Sun et al., Mapping out the Degree of Freedom of Hosted Enzymes in Confined Spatial Environments, Chem
2019), https://doi.org/10.1016/j.chempr.2019.10.002
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Article
Mapping out the Degree of Freedom
of Hosted Enzymes
in Confined Spatial Environments
Qi Sun,1,3,4 Yanxiong Pan,2,4 Xiaoliang Wang, Hui Li, Jasmin Farmakes, Briana Aguila,
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Zhongyu Yang, * and Shengqian Ma1,5,*
2,
SUMMARY
The Bigger Picture
The integration of enzymes with solid materials is crucial for promoting their
industrialization. Understanding the enzyme behavior upon association within
a confined space, though of fundamental importance for biocomposite develop-
ment, remains a persistent, unresolved challenge. Here, we present a compre-
hensive elucidation of the spatial environment’s impact on hosted enzymes’
degree of freedom and, consequently, their accompanying reactivity. Site-
directed spin labeling in combination with electron paramagnetic resonance
spectroscopy allows the direct detection of host-guest interactions at atomic
resolution, while the tailorable synthesis of covalent organic frameworks
The understanding of spatial
enzyme arrangement upon
association with porous materials
in a confined space is essential for
biocomposite development for
numerous applications in the field
of catalysis, medicine, and
separations. In confined
environments, surface properties,
such as wettability, play a
(
COFs) enables an evaluation of factors affecting such interactions. Specifically,
lysozyme is found to be more constrained and less active along with increasing
hydrophilicity of the COFs. These results support the establishment of a connec-
tion between the hydrophilicity of the spatial environment and the resulting bio-
composites’ reactivity, enabling the prediction of the performance of unknown
biocomposites. This study provides a unique insight into the mechanistic path-
ways underpinning biocatalysis.
significant role in addition to
geometric features. This work
demonstrates how the
combination of the site-directed
spin labeling (SDSL)-electron
paramagnetic resonance (EPR)
technique and the tunable COF
syntheses offers opportunities for
building an atomic-level picture of
the interactions between the host
materials and biomolecules. We
establish that increasing the host-
material hydrophilicity results in a
more constrained conformation of
lysozyme and thus its decreased
activity. The developed structure-
performance descriptors have
provided direct shreds of
INTRODUCTION
With most practical applications of porous materials reliant on specific interactions
with guest molecules that are based on the host-guest interaction, understanding
this is a necessity to interpret the properties of existing ones and, in turn, inform
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the development of better host materials with a specific function. Host-guest inter-
actions have been tailored and investigated extensively by dialing in the desired
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–4
function,
but information pertaining to such communications is often phenome-
nological and is usually extracted from indirect methods associated with line shifts,
widths, and/or intensities variation derived from spectroscopy such as Fourier trans-
form infrared (FTIR) spectroscopy. This information proved to be incomplete for
elucidating mechanisms underlying function, which often rely on conformational
evidence that the conservation of
the inherent flexibility is essential
to maintain the overall enzyme
catalytic function, which also helps
improve our understanding of
critical cellular mechanisms.
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,6
flexibility and spatial arrangement such as for biomolecules. Therefore, the design
of composite materials relies mainly on laborious and time-consuming trial-and-
error experiments. A correlation developed based on experimentally determined
structure-property relationships to guide the design of efficient formulations would
be ideal; however, both technology and materials innovations are needed.
Enzymes are linear sequences of amino acids that fold to give intricate structures
with specific catalytically active sites, producing highly selective products with
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accelerated reaction rates. Enzyme conformational dynamics play critical roles in
Chem 5, 1–12, December 12, 2019 ª 2019 Elsevier Inc.
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