bioRxiv (Cold Spring Harbor Laboratory),
Год журнала:
2024,
Номер
unknown
Опубликована: Дек. 7, 2024
Abstract
Non-standard
amino
acids
(nsAAs)
that
are
L-phenylalanine
derivatives
with
aryl
ring
functionalization
have
long
been
harnessed
in
natural
product
synthesis,
therapeutic
peptide
and
diverse
applications
of
genetic
code
expansion.
Yet,
to
date
these
chiral
molecules
often
the
products
poorly
enantioselective
environmentally
harsh
organic
synthesis
routes.
Here,
we
reveal
broad
specificity
multiple
pyridoxal
5’-phosphate
(PLP)-dependent
enzymes,
specifically
an
L-threonine
transaldolase,
a
phenylserine
dehydratase,
aminotransferase,
towards
substrates
contain
side
chains
substitutions.
We
exploit
this
tolerance
construct
one-pot
biocatalytic
cascade
achieves
high-yield
18
from
aldehydes
under
mild
aqueous
reaction
conditions.
demonstrate
addition
carboxylic
acid
reductase
module
enable
biosynthesis
may
be
less
expensive
or
reactive
than
corresponding
aldehydes.
Finally,
investigate
scalability
by
developing
lysate-based
route
for
preparative-scale
4-formyl-L-phenylalanine,
nsAA
bio-orthogonal
handle
is
not
readily
market-accessible.
Overall,
work
offers
efficient,
versatile,
scalable
potential
lower
manufacturing
cost
democratize
many
valuable
nsAAs.
Journal of the American Chemical Society,
Год журнала:
2025,
Номер
unknown
Опубликована: Янв. 23, 2025
Visible
light-driven
pyridoxal
radical
biocatalysis
has
emerged
as
a
new
strategy
for
the
stereoselective
synthesis
of
valuable
noncanonical
amino
acids
in
protecting-group-free
fashion.
In
our
previously
developed
dehydroxylative
C–C
coupling
using
engineered
PLP-dependent
tryptophan
synthases,
an
enzyme-controlled
unusual
α-stereochemistry
reversal
and
pH-controlled
enantiopreference
were
observed.
Herein,
through
high-throughput
photobiocatalysis,
we
evolved
set
stereochemically
complementary
PLP
enzymes,
allowing
both
l-
d-amino
with
enhanced
enantiocontrol
across
broad
pH
window.
These
newly
acid
synthases
permitted
use
range
organoboron
substrates,
including
boronates,
trifluoroborates,
boronic
acids,
excellent
efficiency.
Mechanistic
studies
unveiled
unexpected
racemase
activity
earlier
enzyme
variants.
This
promiscuous
was
abolished
shedding
light
on
origin
enantiocontrol.
Further
mechanistic
investigations
suggest
switch
proton
donor
to
account
stereoinvertive
formation
highlighting
stereoinversion
mechanism
that
is
rare
conventional
two-electron
enzymology.
Journal of the American Chemical Society,
Год журнала:
2024,
Номер
146(32), С. 22476 - 22484
Опубликована: Июль 4, 2024
Visible
light-driven
pyridoxal
radical
biocatalysis
has
emerged
as
a
promising
strategy
for
the
stereoselective
synthesis
of
valuable
noncanonical
amino
acids
(ncAAs).
Previously,
use
well-tailored
photoredox
catalysts
represented
key
to
enable
efficient
phosphate
(PLP)
enzyme-catalyzed
reactions.
Here,
we
report
PLP-dependent
threonine
aldolase-catalyzed
asymmetric
α-C–H
alkylation
abundant
using
Katritzky
pyridinium
salts
alkylating
agents.
The
engineered
aldolases
allowed
this
redox-neutral
proceed
efficiently,
giving
rise
challenging
α-trisubstituted
and
-tetrasubstituted
ncAA
products
in
protecting-group-free
fashion
with
excellent
enantiocontrol.
Mechanistically,
enantioselective
α-alkylation
capitalizes
on
unique
reactivity
persistent
enzymatic
quinonoid
intermediate
derived
from
PLP
cofactor
acid
substrate
allow
novel
C–C
coupling.
Surprisingly,
photobiocatalytic
process
does
not
require
well-established
operates
through
an
unconventional
photoinduced
generation
involving
PLP-derived
aldimine.
ability
develop
reactions
without
relying
classic
photocatalysts
or
photoenzymes
opens
up
new
avenues
advancing
intermolecular
that
are
known
either
organic
chemistry
enzymology.
Journal of the American Chemical Society,
Год журнала:
2025,
Номер
unknown
Опубликована: Апрель 24, 2025
The
difficulty
for
N-unprotected
α-substituted
glycinates
as
α-C
nucleophiles
originates
from
both
competing
N
nucleophilic
interference
and
steric
hindrance
of
the
α
substituent,
which
makes
direct
asymmetric
alkylation
with
Morita-Baylis-Hillman
(MBH)
adducts
especially
challenging.
Given
wide
utilization
α-quaternary
chiral
glutamic
acid
derivatives
in
therapeutic
studies,
we
took
advantage
biomimetic
carbonyl
catalysis
to
achieve
their
efficient
synthesis.
A
bifunctional
centrally
pyridoxal,
featured
an
expanded
catalytic
cavity
reduced
around
aldehyde
group,
was
designed
synthesized.
In
this
work,
describe
novel
pyridoxal
enabled
MBH
acetates.
broad
range
multiple
modifications
were
produced
high
reactivity
excellent
stereocontrol.
Journal of the American Chemical Society,
Год журнала:
2024,
Номер
146(33), С. 23321 - 23329
Опубликована: Авг. 6, 2024
Pyridoxal-5'-phosphate
(PLP)
and
derivatives
of
this
cofactor
enable
a
plethora
reactions
in
both
enzyme-mediated
free-in-solution
transformations.
With
few
exceptions
each
category,
such
chemistry
has
predominantly
involved
two-electron
processes.
This
sometimes
poses
significant
challenge
for
using
PLP
to
build
tetrasubstituted
carbon
centers,
especially
when
the
reaction
is
reversible.
The
ability
access
radical
pathways
paramount
broadening
scope
catalyzed
by
coenzyme.
In
study,
we
demonstrate
PLP-based
intermediate
engage
number
C-C
bond-forming
reactions.
By
selection
an
appropriate
oxidant,
single-electron
oxidation
quinonoid
can
be
achieved,
which
subsequently
applied
Through
pathway,
synthesized
series
α-tertiary
amino
acids
esters
investigate
substrate
identify
nonproductive
pathways.
Beyond
acid
model
system,
that
other
classes
amine
substrates
range
small
molecule
reagents
serve
as
coupling
partners
semiquinone
radical.
We
anticipate
versatile
species
will
central
development
novel
