Trisubstituted Pyrrolinones as Small-Molecule Inhibitors Disrupting the Protein-RNA Interaction of LIN28 and Let-7

Article abstract of DOI:10.1021/acsmedchemlett.0c00546

Modulation of protein-RNA interaction (PRI) using small molecules is a promising strategy to develop therapeutics. LIN28 is an RNA-binding protein that blocks the maturation of the tumor suppressor let-7 microRNAs. Herein, we performed a fluorescence polarization-based screening and identified trisubstituted pyrrolinones as small-molecule inhibitors disrupting the LIN28-let-7 interaction. The most potent compound C902 showed dose-dependent inhibition in an EMSA validation assay, enhanced thermal stability of the cold shock domain of LIN28, and increased mature let-7 levels in JAR cells. The structure-activity relationship study revealed key structural features contributing to either PRI inhibition or stabilization of protein-protein interaction (PPI). The pyrrolinones identified in this study not only represent a new class of LIN28-binding molecules that diversify the limited available LIN28 inhibitors but also represent the first examples of small molecules that showed substituent-dependent PRI inhibitory and PPI activating activities.

Full text of DOI:10.1021/acsmedchemlett.0c00546

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Letter
Trisubstituted Pyrrolinones as Small-Molecule Inhibitors Disrupting
the Protein−RNA Interaction of LIN28 and Let‑7
Lydia Borgelt,|| Fu Li,|| Pascal Hommen,|| Philipp Lampe,|| Jimin Hwang, Georg L. Goebel, Sonja Sievers,
and Peng Wu*
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ABSTRACT: Modulation of protein−RNA interaction (PRI)
using small molecules is a promising strategy to develop
therapeutics. LIN28 is an RNA-binding protein that blocks the
maturation of the tumor suppressor let-7 microRNAs. Herein, we
performed a fluorescence polarization-based screening and
identified trisubstituted pyrrolinones as small-molecule inhibitors
disrupting the LIN28−let-7 interaction. The most potent
compound C902 showed dose-dependent inhibition in an EMSA
validation assay, enhanced thermal stability of the cold shock domain of LIN28, and increased mature let-7 levels in JAR cells. The
structure−activity relationship study revealed key structural features contributing to either PRI inhibition or stabilization of protein−
protein interaction (PPI). The pyrrolinones identified in this study not only represent a new class of LIN28-binding molecules that
diversify the limited available LIN28 inhibitors but also represent the first examples of small molecules that showed substituent-
dependent PRI inhibitory and PPI activating activities.
KEYWORDS: Protein−RNA interaction, RNA-binding protein, Small molecule, LIN28 inhibitor, Substituted pyrrolinone
mall molecules targeting protein−RNA interaction (PRI)
Shold great potential to be therapeutic candidates or
biological probes given the diverse cellular events regulated by
the interaction between RNA and RNA-binding proteins
(RBPs).1 RNA metabolism is regulated by various RBPs,2
whose alteration has been associated with several human
diseases.3−5 There are increasing numbers of reports on small-
molecule RNA binders,6−11 whereas only limited examples of
small molecules targeting RBPs are currently available.12
The microRNA (miRNA)-binding protein LIN28, which
includes two human isoforms LIN28A and LIN28B,13,14
modulates the biogenesis of the let-7 family miRNAs.15,16
Figure 1. Targeting the protein−RNA interaction of LIN28−pre-let-
More specifically, LIN28 binds to both the transcribed primary
7. (A) Simplified overview of the let-7 biogenesis pathway. TUT,
let-7 (pri-let-7) and the Drosha-processed precursor let-7 (pre-
let-7), leading to reduced expression level of mature let-7 by
blockage of Drosha- and Dicer-mediated processing of pri-let-7
and pre-let-7, respectively, and degradation of pre-let-7 via the
recruitment of terminal uridylyltransferases (Figure 1A).17,18
LIN28 features an N-terminal cold shock domain (CSD) and a
C-terminal zinc knuckle domain (ZKD) containing two
CCHC zinc finger motifs. CSD and ZKD are connected by
a flexible linker that allows adapting to the stem lengths of
different let-7 family miRNAs. The CSD binds the stem loop
region and the ZKD interacts with a GGAG motif in the bulge
region of the precursor element (preE) of both pri-let-7 and
pre-let-7 (Figure 1B).19,20 Additionally, LIN28 binds to
mRNAs featuring a GGAGA motif within the loop
structures.21 Targeting the LIN28−let-7 interaction is of
terminal uridylyltransferases. (B) Complex structure of human
LIN28A and preE-let-7f-1 (PDB ID: 5UDZ). The cold shock domain
(CSD) and the zinc knuckle domain (ZKD) are shown in green (left,
surface; right, ribbon), and the preE-let-7f-1 is shown in blue. The
flexible linker connecting the CSD and the ZKD domains is not
resolved in this structure. (C) Representative LIN28 inhibitors 1632,
SB1301, and LI71 and their reported IC50 values.
Special Issue: RNA: Opening New Doors in Medicinal
Chemistry
Received: October 11, 2020
Accepted: February 23, 2021
© XXXX The Authors. Published by
American Chemical Society
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A

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Letter
particular interest from a therapeutic perspective because, on
the one hand, LIN28 is an oncogene that has been found to be
overexpressed in ∼15% of primary human tumors and LIN28
overexpression has been associated with poor clinical
prognosis.22 On the other hand, mature let-7 plays an
important role as a tumor-suppressing miRNA that down-
regulates MYC, RAS, and other oncogenes.16,23 Therefore,
disruption of the Lin28−let-7 interaction using small-molecule
inhibitors to enhance let-7 biogenesis and thus increase the
level of mature let-7 stands as a promising strategy to develop
anticancer therapeutics. Furthermore, the LIN28−let-7 inter-
action has been associated with the regulation of glucose
metabolism24 and other human disease.25
Small-molecule inhibitors targeting LIN28−let-7 interaction
were first reported in 2016,26−28 followed by a few recent
reports (Figure 1C).29−32 The most potent inhibitors showed
micromolar potency in in vitro assays, but suffered from low
potency in cellular evaluations. Very limited structure−activity
relationship (SAR) studies have been performed for even the
most extensively studied class. Therefore, the identification of
new classes of LIN28 inhibitors with scaffolds that are
amenable for further structural optimization will likely lead
to small molecules with improved inhibitory potency. Such
inhibitors will be highly desired as biological probes or as
potential candidates to develop anticancer therapeutics.
Herein, we performed the screening of a library containing
structure-diverse molecules utilizing a fluorescence polarization
(FP) assay to identify inhibitors disrupting the LIN28−let-7
interaction (Figure 2A). A pilot screening of 1400 compounds
FAM-labeled preE-let-7f-1 miRNA (GGGGUAGUGAUUUU-
ACCCUGUUUAGGAGAU-FAM) to identify inhibitors dis-
rupting the LIN28−let-7 interaction (Figure S1A). His-tagged
LIN28A (residues 16−187) was purified using immobilized
nickel affinity chromatography and the His-tag was cleaved by
recombinant TEV protease to remove the potential influence
induced by an artificial charge to LIN28A. In the FP assay,
both His-tagged and untagged LIN28A (residues 16−187)
were titrated into FAM-labeled preE-let-7f-1 and FP was
measured. Increased FP was observed for untagged LIN28A
bound to preE-let-7f-1 (Figure 2B) and His-tagged LIN28A
(Figure S1B). Unlabeled preE-let-7f-1 was used as a positive
control in the FP assay with a tested IC50 of 55 nM, which is
equivalent to the reported value (Figure 2C).29 Additionally,
we synthesized the previously reported inhibitor SB1301 in-
house and tested it in the FP assay (IC50: 27 μM, Figure
2D).27 In light of these results, the FP assay proved to be
sufficiently robust and sensitive to be used for screening of
small-molecule libraries for potential LIN28−let-7 inhibitors.
We performed FP-based screening of an in-house library
containing ∼15 000 natural product-inspired small molecules.
Initial screening was performed for a pilot collection of 1400
compounds in the FP assay. Single concentration measurement
at 30 μM was performed in triplicate. The unlabeled preE-let-
7f-1 miRNA was used as the positive control. FP and total
fluorescence intensity (FI) were recorded. The Z′-factors were
greater than 0.76, conveying high robustness and reliability of
the screening results. Compounds that showed at least 50% FP
inhibition but less than 300% FI of the control were grouped
for the following purity check with a threshold of 85% by LC-
MS. A following manual inspection led to an initial hit list of
six heterocyclic small molecules. To confirm the hits from pilot
screening, we tested the dose-dependent LIN28 inhibition in
the FP assay for the six compounds, among which C902
showed micromolar inhibitory activity (Figure 3A,B).
The pyrrolinone C902 was then resynthesized in-house as
PH-31 with improved purity based on a previously reported
synthetic route involving a three-component Doebner
condensation of an amine, an aldehyde, and a dioxobutanoate
component.33 After testing the IC50 of PH-31 in FP (Figure
3C), its LIN28−let-7 inhibitory activity was verified in an
EMSA, in which compounds that disrupt the formation of the
LIN28−let-7 complex can be identified with a readout
orthogonal to FP. PH-31 showed dose-dependent micromolar
inhibition of the LIN28−let-7 complex (Figures 3D and S2),
while in comparison the unlabeled preE−let-7f-1 completely
inhibited the formation of the protein−RNA complex at 500
nM. In contrast, an FP-inactive analogue C903 did not show
activity in the EMSA (Figure S3). Furthermore, PH-31 showed
concentration-dependent enhancement of the thermal stability
of the CSD of LIN28A in a differential scanning fluorimetry
assay (Figures S4 and S5). Additionally, the treatment of the
human choriocarcinoma cell line JAR that endogenously
expresses LIN28A and LIN28B with PH-31 led to increased
levels of mature miRNAs let-7a and let-7g measured by RT-
qPCR (Figure 3E). It is worth noting that the observed
changes in cellular let-7 level may be attributed to the
polypharmacological nature of the trisubstituted pyrrolinones.
To further probe the inhibitory mechanism of the
pyrrolinone hit C902/PH-31, molecular docking was per-
formed using the reported structure of the LIN28−preE-let-7f-
1 complex.34 A scrutiny of the binding mode between preE-let-
7f-1 and LIN28 CSD did not reveal any deep pocket
Figure 2. FP assay. (A) Small-molecule inhibitors disrupting the
LIN28−let-7 interaction led to low FP signal. PF, polarization
emission filter. (B) FP assay of LIN28A (residues 16−187) titrated to
2 nM FAM-labeled preE-let-7f-1 miRNA, three replicates, error bars
indicate SD. LIN28A-bound preE-let-7f-1 led to increased FP (mP).
(C) Inhibition of the LIN28−let-7 interaction using unlabeled preE-
let-7f-1. (D) Inhibition of the LIN28−let-7 interaction using the
reported LIN28 inhibitor SB1301.
led to the discovery of a pyrrolinone hit C902 that showed low
micromolar inhibitory activity. A following electrophoretic
mobility shift assay (EMSA) verified the dose-dependent
inhibitory activity of the in-house resynthesized hit. Analysis of
hit derivatives and analogues revealed PRI inhibitory SAR
surrounding the pyrrolinone core scaffold and the association
with the protein−protein interaction activating potency of this
series of pyrrolinones.
We used a FP assay to measure the binding between a
truncated human LIN28A containing the CSD and ZKD and a
B
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Figure 3. Screening and validation of inhibitors of the LIN28−let-7 interaction. (A) Structure of the identified C902, which was resynthesized in-
house as PH-31. (B) Inhibitory activity of C902 in the FP assay. (C) Inhibitory activity of PH-31 in the FP assay. (D) PH-31 showed dose-
dependent inhibition of the LIN28−let-7 interaction in EMSA. (E) Treatment of JAR cells with PH-31 led to increased levels of mature let-7a and
let-7g quantified by RT-qPCR. Error bars indicate standard deviation of two independent measurements.
resembling that of the ATP-binding pocket that was targeted
by many kinase inhibitors.35 Whereas there are a few surface
pockets that may accommodate or engage C902 binding, such
as the G7-binding surface dent, the G9-binding surface pocket,
the A10-binding narrow groove, and the U14-binding wide
groove (Figure 4A−C). Docking of C902 onto each of these
surface sites were performed and evaluated based on docking
scores, complementary of shape and charges, and predicted
network of molecular interactions. Among all studied binding
scenarios, the one in which C902 binds at the G9-binding
surface pocket showed to be the most favored, as the K102
residue hooks into the V-shape structural moiety formed by
the aryl substituents at the 1- and 5-positions of the
pyrrolinone core (Figure 4D), together with the formation of
an extensive network of molecular interactions (Figure 4E and
F). The crucial salicylic acid moiety at the 1-position interacts
with K102 via a π−cation interaction and forms hydrogen
bonds with K98 and A101. The carbonyl at the 4-position may
establish a salt bridge via its enol form with K78 and the
benzoyl group interacts with H75 via a T-shaped π−π
interaction. The thiazol-2-yl group at the 5-position stacks
with F73, and the phenyl group at the 5-position interacts with
K102 via a π−cation interaction. Additionally, the 2-carbonyl
group forms a hydrogen bond with K98 and the 3-hydroxy
groups may form a hydrogen bond with K78 through its
ketone form. Docking results at the other sites are less
convincing, since the G7-binding dent is too shallow to form a
strong binding, the A10-binding groove is too narrow to fit
C902, and the U14-binding groove is too wide to anchor
C902.
Figure 4. Binding analysis of pyrrolinone C902 to LIN28 based on
the reported structure of the LIN28−preE-let-7f-1 complex (PDB ID:
5UDZ). (A) Stem loop of preE-let-7f-1 (shown in backbone
comprised of blue ribose and orange phosphate) binding to the
CSD of LIN28A (shown in green surface). (B) Key residues on the
CSD that interact with preE-let-7f-1. Lysine residues are shown in
green backbones, and arginine residues in pale-orange backbones.
Residues including phenylalanine, tryptophan, and histidine that are
involved in π−π stacking interaction are shown in magenta
backbones. Other selected residues that interact with preE-let-7f-1
primarily through hydrogen bond interactions are shown in yellow
backbones. (C) Interactions of let-7f-1 nucleotides with key residues
at the G9−A10-binding groove. Hydrogen bond interactions are
indicated by red dotted lines. (D) Docking of C902 (blue backbone)
into the G9-binding groove on LIN28 CSD (green surface). (E) Key
residues that interact with C902. K78, K98, and K102 are shown in
green backbones; F73 and H75 that are involved in π−π stacking
interactions are shown in magenta backbones; and A101 is shown in
yellow backbone. (F) Interactions of C902 with key residues. Red
dotted lines indicate hydrogen bonds and salt bridges. Green dashed
lines indicate π−π stacking interactions and π−cation interactions.
To analyze the SAR surrounding the trisubstituted
pyrrolinone scaffold of C902, we collected 28 compounds
from the ∼15 000 natural product-inspired library, including
23 pyrrolinones with different substituents at each of the 1-, 4-,
and 5-positions (C879−903, Table 1) and 5 pyrazoles that
were obtained from the pyrrolinones with a further
condensation step with hydrazine (C904−908, Table S1).
The compounds were tested for their dose−response in the FP
assay and the most potent compounds C879 and C880 with
C
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Table 1. LIN28−let-7 Inhibitory Activity of Trisubstituted Pyrrolinones
a
compd ID
R1
R2
R3
IC50 (μM)
bd
,
C879/PH-34
C880/PH-39
C881
C882
C883
C884
C885
C886
C887
C888
C891
C892
C893
C894
C895
C896
C897
C898
C899
C900
C901
C902/PH-31
C903
PH-30
PH-35
PH-36
PH-37
PH-38
PH-43
PH-44
phenyl
phenyl
phenyl
phenyl
thiazol-2-yl
COOH
COOH
COOH
NO2
NO2
COOH
COOH
COOH
COOH
NO2
NO2
COOH
COOH
COOH
COOH
thiazol-2-yl
thiazol-2-yl
thiazol-2-yl
thiazol-2-yl
thiazol-2-yl
thiazol-2-yl
thiazol-2-yl
thiazol-2-yl
thiazol-2-yl
COOH
3-COOH and 4-OH
3-COOH and 4-OH
3-COOH
4-COOH
3-COOH
4-COOH
3-COOH and 4-OH
3-COOH
4-COOH
3-(1H-tetrazol-5-yl)
3-COOH
3-(1H-tetrazol-5-yl)
3-COOH and 4-OH
3-COOH
4-COOH
3-(1H-tetrazol-5-yl)
3-COOH
3-(1H-tetrazol-5-yl)
4-COOH
3-COOH
3-(1H-tetrazol-5-yl)
3-COOH and 4-OH
3-COOH
3-OH and 4-COOH
4-OH
12
bd
,
6
ce
,
>100
>100
>100
>100
30−40
ce
,
ce
,
4-methoxyphenyl
4-methoxyphenyl
4-methoxyphenyl
4-methoxyphenyl
4-methoxyphenyl
4-methoxyphenyl
4-bromophenyl
4-bromophenyl
4-bromophenyl
4-bromophenyl
4-bromophenyl
4-bromophenyl
phenyl
ce
,
ce
,
ce
,
>100
>100
>100
>100
>100
30−40
ce
,
ce
,
ce
,
ce
,
ce
,
ce
,
>100
>100
>100
30−40
ce
,
ce
,
ce
,
ce
,
phenyl
>100
>100
>100
>100
ce
,
4-bromophenyl
4-methoxyphenyl
4-methoxyphenyl
4-bromophenyl
4-bromophenyl
4-bromophenyl
4-bromophenyl
phenyl
ce
,
ce
,
bd
,
5
ce
,
>100
>100
>100
>100
be
,
be
,
be
,
4-OH
b
phenyl
phenyl
thiazol-2-yl
COOH
thiazol-2-yl
thiazol-2-yl
3-NO2 and 4-OH
3-OH and 4-COOH
3-COOH and 4-OH
3-COOH and 4-OH
41
b
16
b
furan-2-yl
3,4-dimethoxyphenyl
5
b
12
a
b
c
Tested in quadruplicate. Starting from a maximum concentration of 60 μM, eight concentrations in total. Starting from 30 μM, eight
d
e
concentrations in total. Data of in-house synthesized compound, PH-series. Extrapolated based on the observed IC50 curves.
tested IC50 values below 30 μM were resynthesized in-house
(PH-34 and PH-39, respectively), together with another seven
compounds there were newly designed and synthesized to
complement the SAR analysis (PH-series, Table 1, Figure S6,
Tables S2−S4). Taken together, the FP dose−response results
showed the crucial role of the salicylic acid moiety at the 1-
position of the pyrrolinone core, as either removal of the 4-
hydroxy group or the 3-carboxylic acid or replacement of the 3-
carboxylic acid with a 4-carboxylic acid reduced activity or led
to loss of activity. The benzoyl substituent at the 4-position of
the pyrrolinone core can be tolerated with a 4-bromo or 4-
methoxy group. Due to limited substitution patterns at the
phenyl group at the 5-position, further structural modifications
need to be performed to determine the SAR at this position.
All tested pyrazoles were inactive in the FP assay. It is worth
noting that the furan-2-carbonyl analogue PH-43 showed
equivalent potency with that of C902 with an IC50 of 5 μM.
This series of pyrrolinones and pyrazoles were previously
reported as stabilizers of the protein−protein interaction (PPI)
involving the plant 14-3-3 proteins,33,36,37 which are small
adapter proteins that interact with functionally diverse protein
partners to play important regulatory roles in vital cellular
events including signal transduction, cell cycle control, and
apoptosis.38 An analysis combining the reported PPI stabilizing
activity between 14-3-3 and the plant plasma membrane H+-
ATPase 2 (PMA2) and PRI inhibitory activity against LIN28−
let-7 revealed in this study showed intriguing SAR information
surrounding the pyrrolinones and pyrazoles (Figure S7). The
pyrrolinones C902, C880 and the furan analogue PH-43 that
showed the most potent LIN28−let-7 inhibitory activities in
our study were compared with compounds PPI-1, C904, and
PPI-2 that showed the most potent 14-3-3−PMA2 stabilizing
activities.33 A general trend is that pyrrolinones that have
shown micromolar inhibitory activity against LIN28−let-7
interaction tended to have minimal stabilizing effects toward
14-3-3−PMA2, all with less than 30% of the stabilizing activity
of that of compound PPI-1, which itself showed a weak
stabilizing potency (EC50: ∼100 μM). In contrast, pyrazole is a
favored scaffold for the stabilization of 14-3-3−PMA2
interaction owing to the rigidity of the pyrazole scaffold that
enables deeper binding to the PPI interface and enlarged
contact surface,33 whereas all the tested pyrazoles C904−908
were inactive against LIN28−let-7 interaction (Table S1).
D
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The salicylic acid moiety, N-3-carboxy-4-hydroxyphenyl
substituent, is important for modulating PPI and PRI and
can be tolerated with a few modifications in either case. The 5-
phenyl of the pyrrolinones, equivalent to the 4-phenyl of the
pyrazoles, plays a crucial role in determining whether the
resulting pyrrolinone is a PRI inhibitor or a PPI activator, as in
the cases C880 and compound PPI-1, whose only difference is
either a 4-carboxy or a 4-nitro group at the 5-phenyl
substituent on the pyrrolinone core. Consistently, the
pyrazoles C904 and PPI-2 that showed the most potent 14-
3-3 PPI stabilizing activity also bear the signature nitro group
at the equivalent position. Additionally, both a 4-carboxy and a
4-(thiazol-2-yl) on the 4-phenyl moiety of pyrrolinones are
shown as being the preferred moieties contributing to LIN28−
let-7 inhibitory activity. In summary, the fact that a certain
substitution pattern is only leading to potency in one direction,
either LIN28−let-7 inhibition or 14-3-3−PMA2 stabilization,
which is “switchable” using another set of substituents, is a
valuable feature for this series of trisubstituted pyrrolinones
and pyrazoles that needs to be studied further.
Fu Li − Chemical Genomics Centre and Department of
Chemical Biology, Max Planck Institute of Molecular
Physiology, Dortmund 44227, Germany
Pascal Hommen − Chemical Genomics Centre and
Department of Chemical Biology, Max Planck Institute of
Molecular Physiology, Dortmund 44227, Germany
Philipp Lampe − Department of Chemical Biology, Max
Planck Institute of Molecular Physiology, Dortmund 44227,
Germany; Compound Management and Screening Center,
Dortmund 44227, Germany
Jimin Hwang − Chemical Genomics Centre and Department
of Chemical Biology, Max Planck Institute of Molecular
Physiology, Dortmund 44227, Germany
Georg L. Goebel − Chemical Genomics Centre and
Department of Chemical Biology, Max Planck Institute of
Molecular Physiology, Dortmund 44227, Germany
Sonja Sievers − Department of Chemical Biology, Max Planck
Institute of Molecular Physiology, Dortmund 44227,
Germany; Compound Management and Screening Center,
Dortmund 44227, Germany
In this study, we identified the trisubstituted pyrroliones as a
new class of small-molecule inhibitors targeting LIN28−let-7
interaction. The most potent compounds C902 and PH-43
showed low micromolar inhibitory potency. The structural
binding analysis showed potential key molecular interactions
between C902 and LIN28A. SAR analysis combining the PRI
inhibitory activity in this study and reported PPI stabilizing
activity of compounds with the same pyrrolinone and closely
related pyrazole scaffolds revealed the pharmacophores
contributing to either LIN28−let-7 inhibition or 14-3-3−
PMA2 stabilization. To the best of our knowledge, this is the
first report of a dual PRI and PPI modulating scaffold, whose
PRI inhibitory and PPI stabilizing activities can be tuned by
carefully choosing different substituents attached to its core.
Therefore, the identified trisubstituted pyrrolinones not only
represent a new LIN28-binding scaffold that diversifies the
limited collection of available LIN28 inhibitors but, more
significantly, stand as a new class of compounds with a
switchable substituent-dependent mechanism of modulation
targeting the challenging PRI and PPI.
Complete contact information is available at:
https://pubs.acs.org/10.1021/acsmedchemlett.0c00546
Author Contributions
||L.B., F.L., P.H., and P.L. contributed equally. The manuscript
was written through contributions of all authors. All authors
have given approval to the final version of the manuscript.
Funding
This work was supported by AstraZeneca, Merck KGaA, Pfizer
Inc., and the Max Planck Society.
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
The authors thank Prof. Herbert Waldmann for constant
support, Dr. Helen Lightfoot and Dr. Donghyun Lim for
discussions on the LIN28−let-7 interaction, Dr. Gavin
O’Mahony for discussion on 14-3-3 stabilization, Dr. Raphael
Gasper for biophysical measurement, and Prof. Rasmus Linser
and Ekaterina Burakova for binding analysis.
ASSOCIATED CONTENT
* Supporting Information
■
sı
ABBREVIATIONS
The Supporting Information is available free of charge at
https://pubs.acs.org/doi/10.1021/acsmedchemlett.0c00546.
■
CSD, cold shock domain; EMSA, electrophoretic mobility shift
assay; FP, fluorescence polarization; PPI, protein−protein
interaction; preE, precursor element; PRI, protein−RNA
interaction; SAR, structure−activity relationship; ZKD, zinc
knuckle domain.
Experimental procedures, supplementary biochemical
and biophysical data, synthetic procedures, compound
characterization data, 1H NMR and 13C NMR spectra of
in-house synthesized compounds (PDF)
REFERENCES
AUTHOR INFORMATION
Corresponding Author
Peng Wu − Chemical Genomics Centre and Department of
Chemical Biology, Max Planck Institute of Molecular
Physiology, Dortmund 44227, Germany; orcid.org/0000-
0002-0186-1086; Phone: +49 (0)231-133-2953;
Email: peng.wu@mpi-dortmund.mpg.de
■
■
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(3) Conlon, E. G.; Manley, J. L. RNA-binding proteins in
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(15), 1509−1528.
Authors
Lydia Borgelt − Chemical Genomics Centre and Department
of Chemical Biology, Max Planck Institute of Molecular
Physiology, Dortmund 44227, Germany
(4) Pereira, B.; Billaud, M.; Almeida, R. RNA-Binding Proteins in
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ACS Medicinal Chemistry Letters
pubs.acs.org/acsmedchemlett
Letter
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https://dx.doi.org/10.1021/acsmedchemlett.0c00546
ACS Med. Chem. Lett. XXXX, XXX, XXX−XXX