Tether influence on the binding properties of tRNALys 3 ligands designed by a fragment-based approach

Article abstract of DOI:10.1039/b921232a

A small library of 1,5-triazole derivatives linking a diaminocyclopentadiol and aromatic ketones has been prepared and screened using NMR and fluorescent techniques against tRNA^Lys₃, the HIV reverse transcription primer. The comparis

Full text of DOI:10.1039/b921232a

View Article Online / Journal Homepage / Table of Contents for this issue
PAPER
www.rsc.org/obc | Organic & Biomolecular Chemistry
Tether influence on the binding properties of tRNALys3 ligands designed by a
fragment-based approach†
a
b
b
a
a
b
Roba Moumn e´ , Val e´ ry Larue, Bili Seijo, Thomas Lecourt, Laurent Micouin* and Carine Tisn e´ *
Received 12th October 2009, Accepted 9th December 2009
First published as an Advance Article on the web 19th January 2010
DOI: 10.1039/b921232a
A small library of 1,5-triazole derivatives linking a diaminocyclopentadiol and aromatic ketones has
Lys
been prepared and screened using NMR and fluorescent techniques against tRNA
3
, the HIV reverse
transcription primer. The comparison of their binding properties to those of their 1,4-triazole isomers,
previously discovered in a fragment-based approach, outlines the influence of the linker on affinity and
binding selectivity in such an approach.
Introduction
structures, since they are often involved in RNA–RNA or RNA–
protein interactions that have an impact on important cellular
processes. If the fragment-based approach has demonstrated its
A fragment-based approach has emerged over the last few years
as a new method for lead identification and is now a well-
8
potential in protein/ligand discovery, the use of such a strategy
1,2
established strategy for drug discovery. The goal is to build
drug leads in pieces, through the identification of weak binding
fragments that are next, either expanded or linked together.
The linking of two fragments that can simultaneously occupy
non-overlapping regions into a larger compound can, under
optimal conditions, give an additive effect on binding energies
9
for the design of RNA ligands is still very limited. We recently
Lys
reported the identification of small ligands of tRNA
3
, the
HIV reverse transcription primer, in a fragment-based approach
using NMR to identify ligands, on the basis of spectral changes
10
induced by their binding to the target. In a primary screen,
diaminocyclopentanol (DACP) and kynuramine were identified
as millimolar binders of the target (Fig. 1). The two fragments
were evolved and connected via a 1,2,3-triazole moiety leading
3
and moreover, entropic benefits will add to this energetic profit.
In principle, the linkers should not perturb the optimal binding
geometry of the two fragments. However, it is difficult to link
two fragments without distorting the binding mode of either
and in some cases the new hybrid ligand may bind differently
than the original unlinked fragments. Plus, the linker itself can
have unfavorable interactions or develop conformational strain,
to a second generation of compounds, such as 1, that are able
Lys
to specifically bind the D stem of tRNA
dissociation constant.
3
with micromolar
4
5
6
thus causing energetic penalties. These observations indicate that
the linkage strategy is crucial and can dramatically influence the
binding properties of the final compounds. As a consequence,
many fragment-based ligands are suboptimal binders because
they do not reach the expectation of additive binding energies
of the fragments pieces. Thus, identifying a linker that allows the
appropriate presentation of the two binding elements may be as
important as the design of the fragments. This can only be achieved
by iterative optimization and binding measurements. In several
reported studies, the optimization of the length and geometry of
7
the linker lead to a great enhancement of the compound potency.
Lys
Fig. 1 Fragments identified as tRNA
3
ligand and compound 1 resulting
However, due to limitations in linker chemistry, it is not always
trivial to change these parameters without modifying the chemical
nature of the tether.
RNA is becoming a valuable target for drug discovery, and of
particular interest are those RNAs that fold into complex tertiary
from fragments evolution and linking by 1,2,3 triazole moiety.
The ligation of two molecules via a 1,2,3-triazole moiety is a
very popular strategy in chemical biology. Due to their high
11
potential for association with biological targets through hydrogen
bonding and dipole interactions, triazoles can generally be more
than passive linkers and contribute to the binding energy of the
compound to its target. In order to study more deeply the influence
of the linker on the binding of our compounds, we were interested
in changing the 1,4-triazole moiety for its 1,5-triazole isomer. Such
a modification was expected to change the orientation between the
two fragments without modifying the chemical nature or the size of
the linker. Indeed, even though the presence of a methylene group
between the fragments and the linker gives a partial motional
a
Chimie Th e´ rapeutique, Universit e´ Paris Descartes, CNRS UMR 8638,
avenue de l’Observatoire, 75006, Paris, (France). E-mail: laurent.
4
micouin@parisdescartes.fr; Fax: +33 143-29-1403
b
Cristallographie et RMN biologiques, Universit e´ Paris Descartes, CNRS
UMR 8015, 4 avenue de l’Observatoire, 75006, Paris, (France). E-mail:
carine.tisne@parisdescartes.fr ; Fax: +33 153-73-9925
Electronic supplementary information (ESI) available: Experimental
procedures and NMR data obtained for all compounds. See DOI:
0.1039/b921232a
†
1
1
154 | Org. Biomol. Chem., 2010, 8, 1154–1159
This journal is © The Royal Society of Chemistry 2010

View Article Online
freedom to the substituents, the 1,4-linkage induces a linear
orientation while the 1,5-isomer forces the folding into an angular
geometry, preventing a fully extended conformation from being
reached. Thus, any difference obtained in the binding properties
should result only from the way the two fragments are presented
to the target. We report here the preparation of a small library of
1
,5-disubstituted triazoles linking DACP and different aromatic
Lys
ketones and the comparison of their affinities toward tRNA
3
10
to the 1,4-regioisomers previously reported (Fig. 2). In this new
family of analogues, due to the geometry of the tether, the two
fragments are brought closer together compared to their 1,4-
counterpart. The results show how the orientation of the two
fragments can have a substantial impact on the location of the
binding sites on the RNA target.
Fig. 2 Libraries of 1,4- and 1,5-triazoles linking DACP and aromatic
ketones.
Scheme 1 Synthesis of 1,5-disubstituted 1,2,3-triazole derivatives by
RuAAC.
After cleavage of the Boc-protective group, diamines 5 were
obtained as their hydrochloride salts and their binding properties
Results and discussion
Lys
towards tRNA
3
were evaluated. (Scheme 2)
Synthesis of a 1,5-triazole linked library
The popularity of 1,4-disubstituted triazoles for establishing
connections in chemical biology is likely due to the ease of their
preparation by the copper-catalyzed 1,3-dipolar cycloaddition of
12
an azide and an alkyne (CuAAC). On the other hand, 1,5-
13
isomers have been only scarcely explored so far, although their
preparation can be easily accomplished by a ruthenium-catalyzed
azide–alkyne cycloaddition reaction (RuAAC), recently reported
14
by Fokin and coworkers. This reaction furnishes the triazole
derivatives with virtually a total 1,5-regioselectivity. The compat-
ibility of the reaction with many functional groups suggests its
possible application to the connection of complex functionalized
molecules. Thus, we used these conditions for the preparation of
the desired compounds.
Scheme 2 Deprotection of 1,5-disubstituted 1,2,3-triazole derivatives.
Lys
Analysis of the impact of the linker on tRNA
fluorescence and NMR spectroscopies
3
binding by
The azido-derivatives 2 required for the cycloaddition were
obtained from the corresponding commercially available a-
bromo-ketones. (Scheme 1) The alkyne derivative 3 was ob-
tained by O-alkylation with propargyl bromide of racemic 2,4-
diaminocyclopentanol, which was prepared by reductive opening
Some of the prepared compounds being fluorescent, we used
a fluorescence-quenching assay to estimate their dissociation
Lys
constant (K
d
) to tRNA
3
, as previously reported. The assay was
conducted in the presence of KCl (50 mM) in order to limit any
non-specific electrostatic interaction. The observed binding curves
15
of the corresponding bicyclic hydrazine. Compounds 2 were
mixed with alkyne 3 in the presence of Cp*RuCl(COD) in
THF. The 1,5-substituted triazole derivatives 4 were obtained
after chromatographic purification in moderate to good yields. The
selective formation of the 1,5-regioisomer of 4 was unambiguously
confirmed by the chemical shifts of C(4) and C(5) ranging
between 132 and 135 ppm, which differ clearly from those of the
corresponding 1,4-isomers (C(5) and C(4) in the range of 124–126
are shown in Fig. 3. In general, the K
d
values obtained for the
1,5-triazole derivatives are in the micromolar range, as for the
10
1,4-isomers (Table 1). Thus, altering the orientation of the two
fragments does not significantly alter the dissociation constant.
The binding sites of all the newly synthesized compounds were
then analyzed by NMR spectroscopy in the window corresponding
to the signals of the imino-hydrogen atoms of the RNA. The
significant NMR chemical shift perturbations (CSP) induced by
16
Lys
and 143–146 ppm respectively).
ligands 5a–e reveal an interaction with the D stem of tRNA
3
,
This journal is © The Royal Society of Chemistry 2010
Org. Biomol. Chem., 2010, 8, 1154–1159 | 1155

View Article Online
Lys
Table 1 Dissociation constant to tRNA
3
obtained by fluorescence-
quenching titration. The value of K
d
are indicated with the 95% confidence
interval in parenthesis
a
Compound
K
d
/mM
d
K /mM of the 1,4-triazole isomer
5
5
5
b
c
f
3.6 (1.9–6.7)
5.3 (3.3–9.6)
7.2 (3.7–12.7)
1.8 (0.6–2.2)
1.2 (0.8–6.4)
6 (1.2–9.3)
a
From ref. 10
Fig. 3 Fluorescence titrations of compounds (a) 5b, (b) 5c and (c) 5f with
Lys
tRNA
3
.
with an additional binding site appearing in the T stem for some
of them (see the ESI†).
Compounds 5a–e all bind to the D stem albeit with some
discrepancies. For instance, compound 5e binds very weakly with
only small CSP, even for a 1 : 4 tRNA : ligand ratio, whereas
Lys
the others induce the disappearance of the tRNA
3
D arm
imino groups resonances, suggesting a different dynamic for the
interaction of this compound. Compounds 5c and 5g have a clear
second binding site in the T arm, as revealed by strong CSP or
disappearance of some NMR peaks of the imino groups at high
ligand : tRNA ratio (4 : 1 or over). Moreover, the interaction of
compounds 5c and 5g involve all the imino groups of the T stem
Fig. 4 NMR chemical shift mapping of the secondary binding site of
Lys
15
compound 5c on tRNA
3
. (a) Reference TROSY spectra of N-labelled
Lys
tRNA
3
(0.2 mM) is in black whereas the spectrum in red is the TROSY
Lys
Lys
spectra of tRNA
3
mixed with compound 5c. (b) Mapping on tRNA
3
(
Fig. 4). Interestingly, none of their corresponding 1,4-isomers
structure (PDB code 1FIR) of the T stem secondary binding site of
bind to the T stem at a similar ligand : tRNA ratio.
compound 5c in magenta.
The comparison of the binding properties of the 1,4-triazole
1
, the 1,5-triazole 5b, and the previously reported ester-linked
The optimization of the linking strategy is an effective way
to enhance the efficiency of a ligand discovered in a fragment-
based approach and this strategy has been frequently outlined for
the optimization of ligands for proteins bearing a single binding
10b
compound 6, which all connect the same fragments, allows
for further investigation of the impact of the linker on tRNA
binding (Fig. 5).
The ester-linked derivative 6 strongly binds to the D stem and
has also a weak second site of interaction with the T stem that
appears starting from a 1 : 4 tRNA : ligand ratio. The 1,4-triazole
Lys
3
1
pocket. The situation is different when working on ribonucleic
targets, since topologically complex RNAs are known to poten-
tially possess multiple binding sites. Selectivity is therefore highly
desired, and generally more challenging to reach than affinity.
1
is highly selective of the D stem, even at a high ligand : tRNA
17
ratio, while the 1,5-triazole 5b exhibits two binding sites located
in the T and D stems. Nevertheless, the binding of 5b to the T
stem is different from that of compound 6. Indeed, the intensities
of the NMR signals relative to W55, G65, T54 are more altered
in the presence of 5b than 6. Since the imino protons are buried
inside the helix, these observations suggest that the 1,5-triazole
linkage allows compound 5b to more deeply enter the T arm to
come nearest to its imino groups.
As outlined by numerous crystallographic studies, interactions
between small molecules and RNA are known to involve a large
number of direct or indirect water-mediated contacts, a reason
18
why good binders are generally promiscuous ligands. As a
consequence, “good” fragments will probably lead to strong but
rather “universal” binders if connected through flexible linkers.
19
This work, as well as other recent publications in this field,
suggests that a rigid linker, able to lock the connected fragments
1
156 | Org. Biomol. Chem., 2010, 8, 1154–1159
This journal is © The Royal Society of Chemistry 2010

View Article Online
into a spatial arrangement, might introduce some site selectivity on
a complex structured ribonucleic target such as transfer RNAs. In
our case, interaction with the T stem seems to be disabled by linkers
imposing a long distance between the two fragments, whereas a
closer spatial proximity between the two fragments introduced
by the 1,5-triazole makes interaction with the T stem possible.
To confirm this hypothesis, compound 10 was prepared using a
triazine as a linker. The longer distance and higher angle between
the two fragments imposed by this linker allow the substituents to
point opposite one to the other in an extended conformation.
Thus, cyanuric chloride was treated with DACP in the presence
of K
2
CO in dichloroethane under reflux. Compound 8 was
3
obtained in rather a modest yield of 36%. This can be explained
by the instability of the product in the reaction mixture, due to
the substitution of its triazine moiety by the in situ-generated
chloride ion, a side reaction that proved to be difficult to
control (Scheme 3). a-Hydroxynaphtylacetophenone was selected
as an aromatic ketone fragment. The corresponding alcohol was
20
prepared according to a known method and introduced on
compound 8 after deprotonation with sodium hydride in THF,
giving the corresponding triazine derivative 9, in 26% yield.
Finally, the Boc-protective groups were cleaved using a saturated
solution of hydrogen chloride in ethyl acetate.
Scheme 3 Synthesis of 1,3-triazine-linked derivative from cyanuric
chloride.
The NMR TROSY experiments showed that 1,3,5-triazine 10
interacts selectively with the D stem, with a dissociation constant
of 1.4 mM, and targets the same part of the RNA as the same imino
proton involved in the interaction (Fig. 6). This result confirms the
role of the linker as a key player for the binding selectivity, showing
therefore, that a linear geometry is required for the selectivity to
the D arm whereas the orientation of the fragments imposed by
the 1,5-triazole linkage allows its binding to the T arm.
Fig. 5 Study of the impact of the linker chemistry on the binding to
Lys
15
Lys
The first step of HIV reverse transcription is the base pairing
tRNA
3
. TROSY experiment of N-labelled tRNA
3
alone (0.2 mM) in
Lys
Lys
of tRNA
to the viral genomic RNA, at its primer-binding site
black and tRNA
3
mixed with compound (a) 6, (b) 1 and (c) 5b at 0.8 mM,
3
in red. Dissociation constants measured by fluorescence spectroscopy are
indicated on each spectrum.
(PBS), which is able in turn to recruit the reverse transcriptase
specifically and start the viral replication. The interaction site of
This journal is © The Royal Society of Chemistry 2010
Org. Biomol. Chem., 2010, 8, 1154–1159 | 1157

View Article Online
Conclusion
In this work, we have shown that small fragments, able to interact
Lys
weakly with the D or T stem of tRNA
3
, can be connected by
triazoles to furnish better ligands with improved affinity and, in
some cases, selectivity. This improvement of selectivity is mainly
controlled by the geometry of the linker, rather than its chemical
Lys
nature. As D and T stems of tRNA
3
are both involved in the first
steps of the HIV reverse transcription, the development of ligands
able to bind to each or both sites is of interest, and might be feasible
by a better exploration of conformational space accessible by rigid
linkers. This work is ongoing in our laboratories.
Experimental
NMR Experiments
Experiments were recorded on a Bruker Avance DRX 600
spectrometer equipped with a cryofit system (60 mL) enabling
us to connect the cryoprobe to a Gilson 215 liquid handler
controlled by the NMR console (Bruker BEST system). All NMR
◦
22
experiments were conducted at 20 C. TROSY spectra with
23
watergate sequence for solvent suppression were recorded using
samples containing 0.2 mM of N-labelled tRNA
as previously reported, for ligand concentration of 1 or 4
equivalents in a 10 mM phosphate buffer at pH 6.5 and 50 mM
KCl. Samples were prepared in a total volume of 200 mL in 96-
well plates and the injected sample volume was 180 mL.
1
5
Lys
3
, produced
24
Fluorescence titrations
◦
Fluorescence titrations were conducted at 25.0 C on a JASCO
spectrofluorimeter. Excitation and emission wavelengths were
341 and 478 nm, respectively, for 5b and 10, 300 and 415 nm,
respectively, for 5c, and 336 and 403 nm, respectively, for 5f. The
excitation and emission bandwidths were 10 nm. Fluorescence
titration experiments were performed by adding increasing con-
centrations of nucleic acid to a fixed amount of ligand (2 or 4 mM)
in a phosphate buffer (10 mM, pH 6.5) for a salt concentration of
Fig. 6 Analysis of the binding properties of compound 10. (a) NMR
Lys
chemical shift mapping of the binding site of compound 10 on tRNA
3
imino groups at 1 : 4 molar ratio. (b) Fluorescence titration of compound
Lys
1
0 with tRNA
3
d
. The value of K is indicated with the 95% confidence
interval in parenthesis.
5
0 mM KCl. Fluorescence intensities were corrected for dilution
and were fitted using eqn (1). Confidence limits on the K were
estimated by Monte-Carlo sampling using the MC-Fit program.
d
22
Lys
tRNA
3
with the viral RNA is located in its acceptor and T
arm. The formation of this reverse transcription initiation complex
(
1)
requires the chaperone activity of the viral nucleocapsid protein
Lys 21
that is known to bind to the D-arm of tRNA
3
.
Thus, small
where I
intensity at a given concentration of RNA, I
intensity at the plateau, n: number of RNA binding sites on the
0
: fluorescence intensity without RNA, I: fluorescence
molecules that bind to either the D arm or the acceptor and T
arms are potential leads for the inhibition of the formation of the
HIV-1 reverse transcription initiation complex. Within the ligands
that we reported up to now, only few binders of the T stem were
discovered, and the NMR CSP on the imino groups obtained
with these compounds were rather weak, although the DACP
fragment has a major binding site in this arm. We have therefore
considered the T stem as much more challenging to target with
small molecules than the D stem. Thus discovery that changing
the geometry of the linker allows for directing the ligand to the T
arm is valuable and bring new insight in order to further develop
ligands of this stem.
•
: fluorescence
ligand, L
t
: total concentration of RNA, N : total concentration of
t
ligand.
Acknowledgements
This work was supported by the French AIDS national agency
(ANRS), the 6th framework program of the European Union
(FSG-V-RNA) and the national agency for research (ANR PCV).
P. Leproux is acknowledged for MS analyses.
1
158 | Org. Biomol. Chem., 2010, 8, 1154–1159
This journal is © The Royal Society of Chemistry 2010

View Article Online
References
Chem., 2008, 3, 715; (d) G. C. Tron, T. Pirali, R. A. Billington, P. L.
Canonico, G. Sorba and A. A. Genazzani, Med. Res. Rev., 2008, 28,
278.
1
Fragment-based Approaches in Drug Discovery, ed. W. Jahnke and
D. A. Erlanson, vol. 34 in series Methods and Principles in Medicinal
Chemistry, ed. R. Mannhold, H. Kubinyi and G. Folkers, Wiley-VCH,
Weinheim, Germany, 2006.
12 (a) V. V. Rostovtsev, L. G. Green, V. V. Fokin and K. B. Sharpless,
Angew. Chem., Int. Ed., 2002, 41, 2596; (b) C. W. Tornøe, C. Christensen
and M. Meldal, J. Org. Chem., 2002, 67, 3057.
2
3
4
(a) C. W. Murray and D. C. Rees, Nat. Chem., 2009, 1, 187; (b) D. C.
Rees, M. Congreve, C. W. Murray and R. Carr, Nat. Rev. Drug
Discovery, 2004, 3, 660.
13 For examples see: (a) A. Tam, U. Arnold, M. B. Soellner and R. T.
Raines, J. Am. Chem. Soc., 2007, 129, 12670; (b) D. Imperio, T. Pirali,
U. Galli, F. Pagliai, L. Cafici, P. L. Canonico, G. Sorba, A. A. Genazzani
and G. C. Tron, Bioorg. Med. Chem., 2007, 15, 6748; (c) U. Pradere, V.
Roy, T. R. McBrayer, R. F. Schinazi and L. A. Agrofoglio, Tetrahedron,
2008, 64, 9044; (d) Y. Chen, M. Lopez-Sanchez, D. N. Savoy, D. D.
Billadeau, G. S. Dow and A. P. Kozikowski, J. Med. Chem., 2008, 51,
3437; (e) M. Chemama, M. Fonvielle, M. Arthur, J. M. Val e´ ry and M.
Etheve-Quelquejeu, Chem.–Eur. J., 2009, 15, 1929.
14 (a) L. Zhang, X. Chen, P. Xue, H. H. Y. Sun, I. D. Williams, K. B.
Sharpless, V. V. Fokin and G. Jia, J. Am. Chem. Soc., 2005, 127, 15998;
(b) B. C. Boren, S. Narayazn, L. K. Rasmussen, L. Zhang, H. Zhao, Z.
Lin, G. Jia and V. V. Fokin, J. Am. Chem. Soc., 2008, 130, 8923.
15 (a) A. P e´ rez Luna, M.-A. Ceschi, M. Bonin, L. Micouin, H.-P. Husson,
S. Gougeon, G. Estenne Bouthou, B. Marabout, M. Sevrin and P.
George, J. Org. Chem., 2002, 67, 3522; (b) A. P e´ rez-Luna, M. Bonin,
L. Micouin and H.-P. Husson, J. Am. Chem. Soc., 2002, 124, 12098.
16 F. Zhang, B. Bernet, V. Bonnet, O. Dangles, F. Sarabia and A. Vasella,
Helv. Chim. Acta, 2008, 91, 608.
17 (a) J. Kondo, B. Fran c¸ ois, A. Urzhumtsev and E. Westhof, Angew.
Chem., Int. Ed., 2006, 45, 3310; (b) J. Kondo, M. Hainrichson, I.
Nudelman, D. Shallom-Shezifi, C. M. Barbieri, D. S. Pilch, E. Westhof
and T. Baasov, ChemBioChem, 2007, 8, 1700; (c) N. Moitessier, E.
Westhof and S. Hanessian, J. Med. Chem., 2006, 49, 1023.
18 For a discussion on this problem, see for instance: A. Ironmonger, B.
Whittaker, A. J. Baron, B. Clique, C. J. Adams, A. E. Ashcroft, P. G.
Stockley and A. Nelson, Org. Biomol. Chem., 2007, 5, 1081.
19 (a) S. T. Meyer and P. J. Hergenrother, Org. Lett., 2009, 11, 4052;
(b) Z. Xiao, N. Zhang, Y. Lin, G. B. Jones and I. H. Goldberg, Chem.
Commun., 2006, 4431.
(a) W. P. Jencks, Proc. Natl. Acad. Sci. U. S. A., 1981, 78, 4046; (b) W. B.
Turnbull, B. L. Precious and S. W. Homans, J. Am. Chem. Soc., 2004,
1
26, 1047.
(a) S. Shuker, P. J. Hadjuk, R. P. Meadows and S. W. Fesik, Science,
996, 274, 1531; (b) E. T. Olejniczak, P. J. Hadjuk, P. A. Marcotte, D. G.
1
Nettesheim, R. P. Meadows, R. Edalji, T. F. Holzman and S. W. Fesik,
J. Am. Chem. Soc., 1997, 119, 5828.
5
6
7
C. H. R o¨ hrig, C. Loch, J.-Y. Guan, G. Siegal and M. Overhand, Chem.
Med. Chem., 2007, 2, 1054.
S. Chung, J. B. Parker, M. Bianchet, M. Amzel and J. T. Stivers, Nat.
Chem. Biol., 2009, 5, 407.
(a) D. J. Maly, I. C. Choong and J. A. Ellman, Proc. Natl. Acad. Sci.
U. S. A., 2000, 97, 2419; (b) P. J. Hajduk, S. B. Shuker, D. G. Nettesheim,
R. Craig, D. J. Augeri, D. Betebenner, D. H. Albert, Y. Guo, R. P.
Meadows, L. Xu, M. Michaelides, S. K. Davidsen and S. W. Fesik,
J. Med. Chem., 2002, 45, 5628; (c) P. J. Hajduk, G. Sheppard, D. G.
Nettesheim, E. T. Olejniczak, S. B. Shuker, R. P. Meadows, D. H.
Steinman, G. M. Carrera, P. A. Marcotte, J. Severin, K. Walter, H.
Smith, E. Gubbins, R. Simmer, T. F. Holzman, D. W. Morgan, S. K.
Davidsen, J. B. Summers and S. W. Fesik, J. Am. Chem. Soc., 1997, 119,
5
818.
8
9
J. R. Thomas and P. J. Hergenrother, Chem. Rev., 2008, 108, 1171.
(a) E. E. Swayze, E. A. Jefferson, K. A. Sannes-Lowery, L. B. Blyn,
L. M. Risen, S. Arakawa, S. A. Osgood, S. A. Hofstadler and R. H.
Griffey, J. Med. Chem., 2002, 45, 3816; (b) L. Yu, T. K. Oost, J. M.
Schkeryantz, J. Yang, D. Janowick and S. Fesik, J. Am. Chem. Soc.,
2
2
003, 125, 4444; (c) M. Mayer and T. L. James, J. Am. Chem. Soc.,
004, 126, 4453; (d) P. P. Seth, A. Miyaji, E. A. Jefferson, K. A. Sannes-
20 R. M. Moriarty, B. A. Berglund and R. Penmasta, Tetrahedron Lett.,
1992, 33, 6065.
Lowery, S. A. Osgood, S. S. Propp, R. Ranken, C. Massire, R. Sampath,
D. J. Ecker, E. E. Swayze and R. H. Griffey, J. Med. Chem., 2005, 48,
21 (a) C. Tisn e´ , Curr. HIV Res., 2005, 3, 147; (b) C. Tisn e´ , B. Roques and
F. Dardel, J. Biol. Chem., 2004, 279, 3588; (c) P. Barraud, C. Gaudin,
F. Dardel and C. Tisn e´ , Biochimie, 2007, 89, 1204.
7
099.
1
1
0 (a) F. Chung, C. Tisn e´ , T. Lecourt, F. Dardel and L. Micouin, Angew.
Chem., Int. Ed., 2007, 46, 4489; (b) F. Chung, C. Tisn e´ , T. Lecourt, B.
Seijo, F. Dardel and L. Micouin, Chem.–Eur. J., 2009, 15, 7109.
1 (a) B. Le Droumaguet and K. Velonia, Macromol. Rapid Commun.,
22 F. Dardel, Comput. Appl. Biosci., 1994, 10, 273.
23 M. Piotto, V. Saudek and V. J. Sklenar, J. Biomol. NMR, 1992, 2,
661.
2
2
008, 29, 1073; (b) C. D. Hein, X.-M. Liu and D. Wang, Pharm. Res.,
008, 25, 2216; (c) A. D. Moorhouse and J. E. Moses, Chem. Med.
24 C. Tisn e´ , M. Rigourd, R. Marquet, C. Ehresmann and F. Dardel, RNA,
2000, 6, 1403.
This journal is © The Royal Society of Chemistry 2010
Org. Biomol. Chem., 2010, 8, 1154–1159 | 1159