a g-quadruplex-containing rna activates fluorescence in a ... · a g-quadruplex-containing rna...
TRANSCRIPT
1
Supplementary Information
A G-Quadruplex-Containing RNA Activates Fluorescence
in a GFP-Like Fluorophore
Hao Huang1, Nikolai B. Suslov2,3, Nan-Sheng Li2, Sandip A. Shelke2,
Molly E. Evans2, Yelena Koldobskaya1, Phoebe A. Rice2,*, Joseph A. Piccirilli1,2,*
1Department of Chemistry, University of Chicago, Chicago, IL, 60637, USA.
2Department of Biochemistry and Molecular Biology, University of Chicago,
Chicago, IL, 60637, USA.
3Present address: Takeda California, San Diego, CA, 92121, USA
*Corresponding author e-mail: [email protected] or [email protected]
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Supplementary Results
Supplementary Note - Synthesis protocol of fluorophore analogues
(Z)-4-(4-Hydroxybenzylidene)-1,2-dimethyl-1H-imidazol-5(4H)-one (HBI) was
synthesized according to a procedure described previously1. 1H NMR
(CD3OD/TMS) 8.00 (d, 2H, J = 9.0 Hz), 7.02 (s, 1H), 6.84 (d, 1H, J = 9.0 Hz)
3.19 (s, 3H), 2.40 (s, 3H).
(Z)-4-(3-Fluoro-4-hydroxybenzylidene)-1,2-dimethyl-1H-imidazol-5(4H)-one
(MFHBI). N-Acetylglycine (209 mg, 1.78 mmol), anhydrous sodium acetate (146
mg, 1.78 mmol), 3-fluoro-4-hydroxybenzaldehyde (250 mg, 1.78 mmol), and
acetic anhydride (0.58 mL) were stirred at 100 ºC for 2 h. After cooling the
reaction to R.T., cold ethanol (5 mL) was added and the reaction mixture was left
at 4 ºC overnight. The resulting solid was collected by filtration, washed with a
small amount cold ethanol, and dried under vacuum to afford (Z)-2-fluoro-4-((2-
methyl-5-oxooxazol-4(5H)-ylidene)methyl)phenyl acetate as a pale yellow solid,
359 mg (77% yield). 1H NMR (CDCl3/TMS) 8.15 (dd, 1H, J = 11.6, 2.0 Hz), 7.70
(d, 1H, J = 8.4 Hz) 7.20 (t, 1H, J = 8.0 Hz), 7.05 (s, 1H), 2.42 (s, 3H), 2.36 (s, 3H).
A mixture of (Z)-2-fluoro-4-((2-methyl-5-oxooxazol-4(5H)-ylidene)methyl)phenyl
acetate (346 mg, 1.32 mmol), ethanol (1.4 mL), 40% aqueous methylamine
(0.28 mL), and potassium carbonate (28 mg) were heated to reflux for 4 h. After
cooling to R.T., the mixture was diluted with water (14 mL), acidified with
concentrated HCl to pH 3, and left at 4 ºC overnight. The yellow solid was
collected by filtration, rinsed with a small amount cold ethanol to give product as
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a yellow solid, 181 mg (59% yield). 1H NMR (DMSO-d6) 8.20 (dd, 1H, J = 13.0,
1.5 Hz), 7.76 (d, 1H, J = 8.0 Hz), 7.00 (t, 1H, J = 8.8 Hz), 6.90 (s, 1H), 3.09 (s,
3H), 2.35 (s, 3H); 13C NMR (DMSO-d6) 169.7, 163.4, 150.7 (d, JC-F = 241 Hz),
147.1 (d, JC-F = 13 Hz), 137.3, 129.6 (d, JC-F = 2.6 Hz), 126.0 (d, JC-F = 7.2 Hz),
124.1 (d, JC-F = 2.6 Hz), 118.8 (d, JC-F = 19 Hz), 117.7 (d, JC-F = 3.3 Hz), 26.2,
15.4; MS (MALDI-TOF) calcd for C12H12FN2O2 [MH+] 235.1, found 235.5.
(Z)-4-[(3-Fluorophenyl)methylene]-2-methyl-5(4H)-oxazolone (FBO). N-
Acetylglycine (4.68 g, 40 mmol), anhydrous sodium acetate (3.28 g, 40 mmol), 3-
fluorobenzaldehyde (5.0 g, 40 mmol), and acetic anhydride (25 mL) were stirred
at 100 ºC for 2 h. After cooling, cold ethanol (60 mL) was added and the reaction
mixture was left at 4 ºC overnight. The resulting solid was collected by filtration,
washed with a small amount cold ethanol, and dried under vacuum to afford
product as a pale yellow solid, 3.72 g (45% yield). 1H NMR (CDCl3/TMS) 7.99
(dd, 1H, J = 10.0, 2.0 Hz), 7.70 (d, 1H, J = 8.0 Hz), 7.40 (m, 1H) 7.20 (dt, 1H, J =
8.0, 2.0 Hz), 7.09 (s, 1H), 2.42 (s, 3H); 13C NMR (CDCl3) 167.6, 167.0, 162.9 (d,
JC-F = 246 Hz), 135.2 (d, JC-F = 8.6 Hz), 133.7, 130.4 (d, JC-F = 8.2 Hz), 129.8 (d,
JC-F = 3.0 Hz), 128.3 (d, JC-F = 2.9 Hz), 118.3 (d, JC-F = 12 Hz), 118.2 (d, JC-F = 11
Hz), 15.9; MS (ES-API) calcd for C11H9FNO2 [MH+] 206.1, found 206.0.
(Z)-4-(3-Fluorobenzylidene)-1,2-dimethyl-1H-imidazol-5(4H)-one (FBI) was
synthesized according to a procedure described previously2,3. 1H NMR
(CDCl3/TMS) 8.05 (m, 1H), 7.74 (d, 1H, J = 7.5 Hz), 7.37 (m, 1H), 7.07 (m, 1H),
7.05 (s, 1H), 3.20 (s, 3H), 2.40 (s, 3H).
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(Z)-4-Benzylidene-1,2-dimethyl-1H-imidazol-5(4H)-one (BI) was synthesized
according to a procedure described previously2,3. 1H NMR (CDCl3/TMS) 8.13 (d,
2H, J = 8.0 Hz), 7.42 (m, 2H), 7.37 (m, 1H), 7.12 (s, 1H), 3.20 (s, 3H), 2.39 (s,
3H).
(Z)-4-(4-Methoxybenzylidene)-1,2-dimethyl-1H-imidazol-5(4H)-one (MeOBI) was
synthesized according to a procedure described previously3. 1H NMR
(CDCl3/TMS) 8.10 (d, 2H, J = 9.0 Hz), 7.05 (s, 1H), 6.92 (d, 2H, J = 9.0 Hz),
3.82 (s, 3H), 3.14 (s, 3H), 2.33 (s, 3H).
(Z)-4-(3-Bromobenzylidene)-1,2-dimethyl-1H-imidazol-5(4H)-one (BrBI) was
synthesized according to a procedure described previously3. 1H NMR
(CDCl3/TMS) 8.36 (s, 1H), 7.99 (d, 1H, J = 7.6 Hz), 7.49 (d, 1H, J = 7.2 Hz),
7.28 (m, 1H), 6.98 (s, 1H), 3.18 (s, 3H), 2.39 (s, 3H); 13C NMR (CDCl3) 170.6,
163.7, 139.7, 136.3, 134.5, 132.8, 130.7, 130.2, 125.2, 122.8, 26.7, 15.8.
(Z)-4-(3,5-difluoro-4-hydroxybenzylidene)-2-methyl-1-(2,2,2-trifluoroethyl)-1H-
imidazol-5(4H)-one (DFHBI-1T) was synthesized according to a procedure
described previously4. 1H NMR (CD3OD/TMS) 7.78 (dd, 2H, J = 8.0, 1.8 Hz),
6.92 (s, 1H), 4.42 (q, 2H, J = 8.8 Hz), 2.40 (s, 3H).
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Supplementary Figure 1. Pre-crystallization characterization of the Spinach RNA. (A).
Binding of Fab BL3-6 to the Spinach_Tag aptamer containing the hairpin graft in P2.2
(GAAACAC). The fit of the data to the Hill equation gives KD = 25 ± 6 nM (open circles).
Wild-type (UUCG) Spinach does not bind to BL3-6 (closed circles). (B). Fluorescence
emission of DFHBI alone (blue), in the presence of Spinach_WT (UUCG, red), or
GAAACAC in the absence (green) or presence (purple) of Fab BL3-6. Excitation
wavelength is 468 nm; spectra are normalized to the molar concentrations of RNA using
the 502 nm emission peak. (C). Gel filtration chromatograms showing UV absorption
profiles. Peaks were normalized to the molar concentrations of samples. The 1:1 Fab-
RNA complex of Spinach_Tag eluted about 20 mL earlier than the RNA alone.
a b
c
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Supplementary Figure 2. The Fab-RNA binding interfaces. (A). The antigenic interface.
The stem-loop of the GAAACAC tag (P2, blue ribbon) binds to a site created by Fab
heavy chain CDRs H1 (red), H2 (green), H3 (purple) and light chain CDR-L3 (orange).
CDR-L1 and -L2 do not make direct contact with the RNA, and do not make any crystal
contacts either. (B). Three other non-antigenic interfaces engaged by symmetry-related
Fabs (green) in the lattice. Contact residues on the Fabs are highlighted in dark grey.
a
b
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Supplementary Figure 3. Fab interactions with the GAAACAC hairpin loop. (A)
Arginine residues 105 and 106 from CDR-H3 (purple) contact G37 (blue) at N7 and the
phosphate, respectively. (B). Phe95 from CDR-L3 (orange) stacks between Tyr62 from
CDR-H2 (green) and nucleobase A40 (blue). Arg110 of CDR-H3 contacts the 4’-oxygen
of the same nucleotide (C). CDR-H2 residue Tyr57 (green) forms a hydrogen-bond to
the 2’-OH of A38, and serines 58 and 60 interact with the W-C face of C41. Nucleotide
A39 stacks between G37 and Tyr 57. A38 also contacts CDR-H1 residue Tyr 34 (red)
by stacking plus a hydrogen bond.
a b
c
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Supplementary Figure 4. Crystal packing and interfaces. (A). Crystal packing of the
Fab-Spinach RNA complex (Fab: green; RNA: brown) in a unit cell. In one dimension,
the arrangement of complexes extends via the terminal stem of the RNA protruding into
a cleft between heavy and light chains from two other symmetry-related molecules. Fab
contacts mediate extensions in the other dimensions. (B). Mode of Fab engaging the
RNA via crystal contacts. The RNA (brown) also contacts multiple Fabs (light green)
from symmetry-related molecules in the lattice, in addition to the paratope interaction
(circled; with the dark green Fab) via antigen-binding site as in Supplementary Fig. 2A.
(C). Fab-Fab interactions contributing to lattice packing. The predominant contacts take
place between the outer surfaces of the light chains (highlighted in red). The oval
indicates 2-fold symmetry along the y-axis (perpendicular to the page).
a
b c
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Supplementary Figure 5. A lone RNA-RNA intermolecular contact involved in crystal
packing. The 5’-phosphate oxygens of G1 from P1 (magenta) form hydrogen bonds with
A38 of a symmetry-related molecule (cyan).
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Supplementary Figure 6. Non-canonical base pairs in Spinach. (A). The non-canonical
purine-purine base pairs A20·G65 and A21·A64 open up stem P1.2 (magenta) at the
floor of the G-quadruplex region (brown-yellow and red). A20 and G65 use their W-C
faces to form two hydrogen bonds while A64 uses its Hoogsteen face to form one
hydrogen bond with the W-C face of A21. (B). Both A12·A73 and A13·A72 in P1
(magenta) form non-canonical base pairs via single N3-N6 hydrogen bonds, splitting P1
into two segments. (C). A non-canonical base pair forms between U18 and U67 towards
the middle of P1.2. Dashed lines indicate hydrogen bonds. Both upstream and
downstream G-C pairs are also displayed. Truncation analysis (Fig. 1C) revealed that
these non-canonical pairs in (B) and (C) are not essential for DFHBI binding and
fluorescence activation.
b c
a
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Supplementary Figure 7. Secondary structure of the Spinach RNA aptamer (A) and
GAAACAC hairpin graft (B) as predicted by mFold1,5. The red circle highlights the hairpin
graft.
a b
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Supplementary Figure 8. Hydroxyl radical (Fe-EDTA) footprinting of Spinach and
Spinach-Fab complex. (A). The P2 (AACAA) loop of Spinach becomes protected from
hydroxyl radical cleavage in the presence of 500 nM Fab. Blue balls in the structure
indicate the sole region of protection. (B). Color plot from footprinting data (blue = more
protection) showing significant reduction of cleavage (protection) from residues G37 to
A40. (C). Solvent accessibility (probe radius = 1.4 Å) by individual nucleotide on Spinach.
The calculated data match with the footprinting results.
a b
c
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Supplementary Figure 9. Solution studies using SAXS. The experimental SAXS
curves (black; 1.0 mg/mL sample concentration) were fitted respectively with theoretical
curves (red) deduced from the crystal structure. In each panel: left – Spinach RNA; right
– Spinach-Fab complex. The model used to generate the theoretical curve is shown in
the bottom-left inset in each panel, and the corresponding Guinier analysis plots with
regression coefficients R are shown as insets at the top-right. The Guinier analysis plots
over the same range of Q values for the 2.0 mg/mL samples gave similar linear fits, R =
0.999 and 0.998, respectively) with no apparent curvature. The 2 number from fitting
suggests reasonable agreement between the observed and calculated profiles6,7. I -
intensities; Q – the scattering vector [(4/) sin]. (B). Experimental (black) and model
derived (red) pair-distance distribution curves for Spinach RNA and Spinach-Fab
complex. R is the distance measured within the molecule. Rg is the calculated radius of
gyration.
a
b
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Supplementary Figure 9 continued. (C). Crystal structure of each model contoured by
the molecular envelope (grey, transparent) in two different views, calculated from the
corresponding pair-distance distribution curve. Envelopes were averaged from 12
repeating DAMMIF calculations assuming uniform density on each object, with no
normalized spatial discrepancy (NSD) outlier being detected and discarded (NSD =
0.728 ± 0.033 for the RNA model, and 0.717 ± 0.010 for the complex).
c
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Supplementary Figure 10. Replacement P1 stems for Spinach truncates. All truncated
constructs retain the non-canonical purine-purine pairs (orange) at the base of the G-
quadruplex motif. Remaining parts of the RNA are omitted for clarity.
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Supplementary Figure 11. Spinach-activated DFHBI fluorescence in the presence of
different cations. All samples contained 5 M RNA, 20 M DFHBI,10 mM Tris-Cl pH 7.5
and cations as indicated. K+ – 100 mM KCl; Na+ – 100 mM NaCl; NH4+ – 100 mM NH4Cl;
N/A – 0.5 mM EDTA pH 8.0 (with the no Mg2+ condition only). See Fig. 2C for full
titrations curves for K+, Na+, and NH4+ in the presence of 5 mM Mg2+.
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Supplementary Figure 12. SHAPE analysis of Spinach and mutants. All lanes
represent products from primer extension reactions using radiolabeled primers. Lanes
labeled ‘Input’ contained primer extension reactions on RNA samples not exposed to the
SHAPE reagent. G and U indicate the lanes mapping the locations of Gs and Us in the
RNA sequence, respectively. Ligand, Mg2+ and K+ were varied as indicated. Data on
[Mg+/K+/DFH+] (lane #5) were analyzed and superimposed onto the crystal structure
(Fig. 2d). A more detailed interpretation of this data is provided in Online Methods.
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Supplementary Figure 13. Crystal structure of DFHBI fluorophore (Deposition code:
CCDC-956054). (A). ORTEP (Oak Ridge Thermal Ellipsoid Plot) diagram of DFHBI
molecule showing the (Z)-configuration. (B). DFHBI packing in the unit cell.
b
a
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Supplementary Figure 14. The Spinach core structure displayed with electron density
maps. (A). DFHBI in its binding site, contoured with the |Fobs|-|Fcal| difference map (green
mesh, RMSD = 3.5σ) from a simulated annealing refinement omitting the ligand. (B) The
binding site and (C) the G-quadruplex in the presence of DFHBI, contoured with feature-
enhanced 2|Fobs|-|Fcal| maps (RMSD = 1.0σ for black mesh, and 2.5σ for blue mesh;
carve = 2.0). The black arrow indicates the linker of DFHBI fluorophore. Color codes of
nucleotides and ligand atoms match Figure 3a.
c
b a
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Supplementary Figure 14 continued. (D) and (E). Two additional projections showing
DFHBI in its binding site contoured with the |Fobs|-|Fcal| difference map (green mesh,
RMSD = 3.5σ) from a simulated annealing refinement omitting the ligand.
d
e
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Supplementary Figure 15. Additional data defines the ligand orientation. The panels
show the fit of a conceptual model ligand containing both bromophenyl and N-
trifluoroethyl groups. Of the eight combinations of ligand geometry and orientation
considered, only one (top left) fits well with both the highest peak in the Br anomalous
difference map and the –CF3 omit map while also agreeing with the overall location of
the ligand outlined by the 2|Fobs|-|Fcal| map. For a higher-resolution 2|Fobs|-|Fcal| map of
the native ligand, see Supplementary Fig 14. Phenix was used to calculate maps and
then superimpose them (to accommodate small unit cell variations)8. The figure was
made using Pymol, with the “carve” parameter set to 1.6 Å (which was necessary to
remove density for neighboring residues in the 2|Fobs|-|Fcal| map).
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Supplementary Figure 16. Mutations in the G-quadruplex and adjacent region diminish
DFHBI fluorescence activation. DFHBI – the unbound fluorophore in buffer; ΔQ1 – first
layer of the G-quadruplex (G23, G27, G54, G59) mutated into pyrimidines; ΔQ2 –
second layer of the G-quadruplex (G22, G26, G57, G61) mutated into pyrimidines; ΔPP
– the A20·G65 and A21·A64 purine pairs at the quadruplex floor (Supplementary Fig. 6a)
mutated into canonical G-C pairs; ΔAdj – three adjacent guanines to the fluorophore
(G23, G28, G54) mutated into pyrimidines. All samples contained 5 M RNA, 20 M
DFHBI in 10 mM Tris-Cl pH 7.5, 100 mM KCl, 5 mM MgCl2.
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Supplementary Figure 17. Deoxynucleotide substitutions in Spinach affect DFHBI
binding and fluorescence activation. Fits of the data to Hill equation gave KD = 380 ±
60 nM for Spinach WT and 1.1 ± 0.3 M for dU50 mutant. Spinach variants containing
either dG23 or dA53 exhibited very little fluorescence activation. These experiments
used the truncated form of Spinach and variants containing a 5 base pair P1 stem from
enzymatic ligation.
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Supplementary Figure 18. Affinity of Spinach for various fluorophore analogs.
(A).Dependence of fluorescence activation on ligand concentration. Assays were
conducted at 30 nM RNA. (B). Inhibition of DFHBI fluorescence activation by competitive
binding of non-fluorescent analogs. The competitive assay included 300 nM (at the KD)
of Spinach and 300 nM DFHBI. A fit of the data to the Hill equation followed by a
calculation with the Cheng-Prusoff equation gave the indicated values of Ki = IC50 / 2. (C).
Chemical structure and KD/KI for each analog.
a b
c
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Supplementary Figure 19. Fluorophore (green) interactions in EGFP and Spinach. (A).
The hydroxybenzylidene imidazolinone fluorophore in EGFP (purple), generated from
residues Tyr66, Thr65 and Gly67, makes hydrogen bonds to amino acid side chains
(PDB code: 2Y0G). (B). Spinach RNA (light blue) mediates hydrogen bonds to DFHBI.
Dashed lines indicate inferred hydrogen-bond contacts to the fluorophores. Atom color
code: O = red, N = blue, F = cyan.
a
b
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Supplementary Figure 20. The overall model and accompanying electron density omit
maps. (A). The Spinach RNA (backbone in orange) with the 2|Fobs|-|Fcal| composite omit
map from simulated annealing, contoured at 2.0σ and carved within 2.0 Å of selected
atoms. (B). Display of the RNA with the same map at 1.0σ and carved within 2.0 Å of
selected atoms.
b a
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Supplementary Figure 21. Conceptual models of the (E)-isomer of DFHBI in the
Spinach binding site. The imidazolinone exocyclic oxygen faces (A) G28 or (B) 2’-
hydroxyl of A53, respectively. Hypothetical hydrogen bonds and hydrophobic
interactions are indicated with dashed lines. U29 is omitted for clarity. Color codes match
Figure 3a.
a
b
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Supplementary Table 1. Data collection and refinement statistics of RNA-
Fab complex structures with DFHBI and its analogs
Ligand DFHBI Ligand-free BrBI DFHBI-1T
Data collection
Beamline APS NECAT
24-ID-C
APS NECAT
24-ID-C
APS GM/CA
23-ID-D
APS NECAT
24-ID-E
Wavelength (Å) 0.9795 0.9795 0.9184 0.9795
Space group C 1 2 1 C 1 2 1 C 1 2 1 C 1 2 1
Cell dimensions
a, b, c (Å) 148.4, 79.6, 95.2 146.9, 80.1, 94.5 146.5, 79.7, 95.3 147.5, 79.0, 94.4
() 90.0, 111.7, 90.0 90.0, 111.9, 90.0 90.0, 111.5, 90.0 90.0, 112.4, 90.0
Resolution (Å) 46.69-2.19
(2.30-2.19)*
2.2, 2.2, 2.4**
45.37-2.40
(2.53-2.40)*
2.4, 2.4, 2.5**
46.43-2.03
(2.07-2.03)*
2.0, 2.4, 2.4**
67.68-3.12
(3.29-3.12)*
3.1, 4.0, 3.1**
Rmerge (%) 5.9 (61.5) 6.6 (53.6) 15.1 (58.9) 19.1 (80.7)
I /I 10.6 (1.8) 10.9 (1.9) 12.8 (0.8) 7.8 (1.6)
Completeness (%) 98.2 (98.3) 96.5 (95.3) 91.1 (44.5) 98.5 (98.4)
Redundancy 3.0 (2.9) 2.9 (2.9) 5.0 (1.9) 3.1 (3.2)
Refinement
Resolution (Å) 46.69-2.19 45.37-2.40 46.43-2.45;
(98.5% completeness)
67.68-3.12
No. reflections 52457 38250 72602
(37296 non-anomalous)
17701
Rwork / Rfree 0.179 / 0.211 0.186 / 0.224 0.184 / 0.220 0.205 / 0.253
No. atoms 5644 5417 5431 5174
Protein 3321 3321 3321 3303
RNA 1815 1819 1815 1815
Ligand/ions 48 2 24 23
Water 460 275 271 33
B-factors (overall) 43.9 44.2 64.0 87.1
Protein 30.5 31.6 44.2 68.8
RNA 70.2 68.9 102.1 120.3
Water 35.9 33.3 45.6 43.1
R.m.s. deviations
Bond lengths (Å) 0.007 0.008 0.002 0.003
Bond angles () 1.17 1.10 0.70 0.54
PDB code 4KZD 4KZE 4Q9Q 4Q9R
*Values in parentheses are for highest-resolution shell.
**Anisotropic resolution limits along a, b, c directions, calculated by using Diffraction Anisotropy Server9.
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Supplementary Table 2. Data collection and refinement of DFHBI structure
DFHBI (C12H9F2N2O2)
Data collection
Formula weight 251.21
Space group P21/c
Cell dimensions
a, b, c (Å) 3.85, 12.55, 21.92
() 90.0, 98.6, 90.0
Crystal system Monoclinic
Wavelenth (Å) 0.71073
Temperature (K) 100
Theta range 1.87 – 23.39 o
Refinement
Highest resolution (Å) 0.90
No. reflections 8353
Independent reflections 1,532
Reflections with I > 4 (Fo) 774
Rint 0.0671
Goodness-of-fit on F2 0.887
Final R indices [I > 2 sigma(I)] R1 = 0.0647, wR2 = 0.1394
R indices (all data) R1 = 0.1334, wR2 = 0.1590
Largest diff. peak and hole 0.257, -0.222 eÅ -3
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Supplementary Table 3. Summary of the Spinach mutant sequences used
in this work.
RNA Sequence
WT
(Spinach_tag)
5’GGACGCGACCGAAAUGGUGAAGGACGGGUCCAGUGCGAAACACGCACUG
UUGAGUAGAGUGUGAGCUCCGUAACUGGUCGCGUC 3’
G28A 5’GGACGCGACCGAAAUGGUGAAGGACGGAUCCAGUGCGAAACACGCACUG
UUGAGUAGAGUGUGAGCUCCGUAACUGGUCGCGUC 3’
G28U 5’GGACGCGACCGAAAUGGUGAAGGACGGUUCCAGUGCGAAACACGCACUG
UUGAGUAGAGUGUGAGCUCCGUAACUGGUCGCGUC 3’
G28C 5’GGACGCGACCGAAAUGGUGAAGGACGGCUCCAGUGCGAAACACGCACUG
UUGAGUAGAGUGUGAGCUCCGUAACUGGUCGCGUC 3’
A53U 5’GGACGCGACCGAAAUGGUGAAGGACGGGUCCAGUGCGAAACACGCACUG
UUGUGUAGAGUGUGAGCUCCGUAACUGGUCGCGUC 3’
Q1 5’GGACGCGACCGAAAUGGUGAAGCACGUGUCCAGUGCGAAACACGCACUG
UUGACUAGAUUGUGAGCUCCGUAACUGGUCGCGUC 3’
Q2 5’GGACGCGACCGAAAUGGUGAACGACUGGUCCAGUGCGAAACACGCACUG
UUGAGUACAGUUUGAGCUCCGUAACUGGUCGCGUC 3’
PP 5’GGACGCGACCGAAAUGGUGCGGGACGGGUCCAGUGCGAAACACGCACUG
UUGAGUAGAGUGUGCGCUCCGUAACUGGUCGCGUC 3’
Adj 5’GGACGCGACCGAAAUGGUGAAGCACGGUUCCAGUGCGAAACACGCACUG
UUGACUAGAGUGUGAGCUCCGUAACUGGUCGCGUC 3’
16 bp
Truncate
5’GGACGCGACCGAUGGAGAAGGACGGGUCCAGUGCGAAACACGCACUGUU
GAGUAGAGUGUGAGCUCCAUCGGUCGCGUC 3’
5 bp
Truncate
5’GGGGAGAAGGACGGGUCCAGUGCGAAACACGCACUGUUGAGUAGAGUGU
GAGCUCCC 3’
3 bp
Truncate
5’GGAGAAGGACGGGUCCAGUGCGAAACACGCACUGUUGAGUAGAGUGUGA
GCUC 3’
1 bp
Truncate
5’GGAAGGACGGGUCCAGUGCGAAACACGCACUGUUGAGUAGAGUGUGAGC
3’
0 bp
Truncate
5’GAAGGACGGGUCCAGUGCGAAACACGCACUGUUGAGUAGAGUGUGAG 3’
WT-acceptor 5’ GGGGAGAAGGACGGGUCCAGUGC 3’
WT-donor 5’ pGAAACACGCACUGUUGAGUAGAGUGUGAGCUCCC 3’
dG23-acceptor 5’ GGGGAGAAGdGACGGGUCCAGUGC 3’
dU50-donor 5’ pGAAACACGCACUGdUUGAGUAGAGUGUGAGCUCCC 3’
dA53-donor 5’ pGAAACACGCACUGUUGdAGUAGAGUGUGAGCUCCC 3’
Ligation
Splint (DNA)
5’ ACAGTGCGTGTTTCGCACTGGACCCGTC 3’
Nature Chemical Biology: doi:10.1038/nchembio.1561
32
Supplementary Table 4. SAXS data collection and scattering derived
parameters
Fab-Spinach complex Spinach RNA
Data collection
Instrument SIBYLS beamline Advanced Light Source Berkeley CA
Beam geometry Superbend synchrotron light 100x100 micron
Wavelength (Å) 1.03
Q range (Å-1) 0.009 – 0.320
Exposure time (s) 1.0
Concentration (mg/mL) 1.0, 2.0
Temperature (K) 283
Structural parameters
Dmax (Å) 160.0 98.0
Rg (Å) from P(r) 46.96 ± 0.74 29.94 ± 0.11
Rg (Å) from Guinier 43.52 ± 0.14 32.04 ± 0.39
46.64 ± 0.14* 31.54 ± 0.24*
I(0) from P(r) (cm-1) 419 460
I(0) from Guinier (cm-1) 410 509
Molecular envelope NSD 0.717 ± 0.010 0.728 ± 0.033
Software employed
Intensity curve fitting CRYSOL10
Guinier analysis AUTORG11
Pair-distance distribution GNOM12
Ab initio analysis DAMMIF13
Structure superposition SUPCOMB14
* For the 2.0 mg/mL sample concentration
Nature Chemical Biology: doi:10.1038/nchembio.1561
33
Supplementary References
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Nature Chemical Biology: doi:10.1038/nchembio.1561