Silica nanostructure with chemo-enzymatic compartmentalization

Date:
August 12, 2021
Source:
Pohang University of Science & Technology (POSTECH)
Summary:
A research team has recently synthesized a chemo-enzymatic
nanostructure that can selectively synthesize one enantiomer while
acting like an artificial organelle in the cell.



FULL STORY ==========================================================================
As COVID-19 vaccinations are well underway, people await a return to
normal life. However, fears also grow due to unforeseen side effects like
the rare thrombosis. In the body, life is maintained by the movement of substances or energy. Chemical reactions are regulated by the presence
of organelles or core structures of cells that accommodate specific
enzymes or cofactors. A nanoreactor with both the activity of a synthetic catalyst, such as an artificial organelle that mimics a cell, and the properties of an enzyme creates a platform for selectively synthesizing
natural enantiomeric bioactive molecules that can respond to pathogens --
such as drugs -- in the body.

However, until now, a nanoreactor with the functions of both a synthetic catalyst and an enzyme for such a platform has not been reported.


==========================================================================
To this, a research team at POSTECH has recently synthesized a
chemo-enzymatic nanostructure that can selectively synthesize one
enantiomer while acting like an artificial organelle in the cell.

A research team led by Professor In Su Lee, Research Professor Amit Kumar,
and Ph.D. candidate Seonock Kim of POSTECH's Department of Chemistry has succeeded in designing a silica nanostructure (SiJAR) as an artificial organelle for selective synthesis of enantiomers in cells. This research finding was selected as the front cover of Angewandte Chemie, and
published online on June 21, 2021.

The first consideration in designing nanostructures for intracellular applications is to stably co-localize and maintain the reactive
surface of catalytic nanocrystals while protecting the enzyme from inactivation. Until now, the catalysis of nature-inspired hollow
nanostructures accommodating catalytic nanocrystals or enzymes, or both,
has only been experimentally proven and has not been demonstrated in
living organisms. This is because microporous closed nanostructures
restrict the entry and co-localization of catalytic nanocrystals and
large-size biomolecules.

The research team synthesized round jar-shaped SiJARs with
chemo-responsive metal-silicate lids by modifying the chemical
composition of a section in the reactor using spatiotemporal-controlled
thermal conversion chemistry. Due to the divided configuration of SiJAR, different catalytic noble metals (Pt, Pd, Ru) were selectively modified
on the lid-section by galvanic reactions.

Subsequently, the lid was opened under mild acidic conditions or an intracellular environment, creating a wide-passage into the shell while shifting the residual metal catalyst of the lid inwards. This open
structure accommodates large enzymes, thus facilitating encapsulation.

The nanoreactor synthesized in this study is composed of silica with
high biocompatibility and by protecting catalytic nanocrystals or
large biomolecules in an open-mouth silica-compartment, it performed
asymmetric aldol reaction with high enantioselectivity via an enzyme-metal co-operative transition state stabilization. In addition, the researchers confirmed that it functions as an artificial catalytic organelle by
stably performing the reaction inside living cells.

The hybrid chemoenzymatic nanodevice, customizable through this
sophisticated solid-state conversion strategy, has a structure and
function similar to that of intracellular organelles, and can be utilized
for synthesizing active therapeutics and bioimaging probes locally inside
cells to be suitable for use in next generation bioimaging and treatment.

"With the results of this research using the unique Nanospace-Confined
Chemical Reactions (NCCR), we look forward to developing the technology
that artificially regulates cell functions," commented Professor In Su
Lee who led the study.

This study was conducted with the support from the Leader Researcher
Program and the National Creative Research Initiative Program of the
National Research Foundation of Korea funded by the Ministry of Science
and ICT of Korea.

========================================================================== Story Source: Materials provided by Pohang_University_of_Science_&_Technology_(POSTECH).

Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Seonock Kim, Nitee Kumari, Jongwon Lim, Sateesh Dubbu, Amit Kumar,
In Su
Lee. Silica Jar‐with‐Lid as Chemo‐Enzymatic
Nano‐Compartment for Enantioselective Synthesis inside
Living Cells. Angewandte Chemie International Edition, 2021; 60
(30): 16337 DOI: 10.1002/anie.202103165 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/08/210812092719.htm

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