Supplementary Material
Table 1:Crystallization and Data Collection
Data set
CTD1
Crystallization PEG 4000, 28.75% to
29.5 %, pH 4.8 Citrate,
condition
0.1 M MgCl2
X-ray source
SBC-CAT 19ID
Advanced Photon Source
(Argonne)
Wavelength
0.97937 Å
(360º , 1º
oscillation)
CTD2
30% PEG 4000,
100 mM Tris-HCl
pH 8.6, 800 mM
LiCl
BIOCARS-14ID
Advanced Photon
Source (Argonne)
0.9795 0.9000 Å
1Å
(180º , 1º
(360º , oscillation)
1º
oscillati
on)
P2(1)2(1)2(1)
P2(1)2(1)2
a=38.389 b=65.939
a=108.99 b=128.53
c=92.306 α=90.000
c=71.44 α=90
β=90.000 γ=90.000
β=90.00 γ=90.00
CTD3
NTD1
4.3M NaCl,
25 % PEG
0.1M Tris-Cl pH 8.5 4000,100 mM
MES Sodium
Salt, pH 6.2,
200 mM
MgCl2
ID14-4, ESRF
BIOCARS(Grenoble)
14ID
Advanced
Photon
Source
(Argonne)
0.97626 Å
0.9000 Å
(360º, 1º oscillation) (180º , 1º
oscillation)
Resolution (Å)
Total number
of reflections
Number of
molecules in
ASU
Completeness
(%)
Redundancy
Rmergeb
50-2.0
15,139
28,037
50-2.2
97,377
20-2.6
31,078
C2
a= 100.06
b=46.21
c=74.18
=90.00
=121.06
=90.00
50-1.3
204,381
8
-
2
2
2x
96 (68.9)
99.7(98.8)
90.6 (90.5)
87.9(60.5)
3.4(3.1)
0.081(0.588)
1.65 (1.66)
0.079 (0.417)
3.3(2.6)
0.056(0.227)
I/σ(I)
28.80(0.73)
97.9(85
.5)
5.3(3.2)
0.076(0
.358)
29.32(3
.67)
16.23(2.83)
13.59 (3.1)
49.3(13.3)
Cell
parameters
(Å)
11(8.2)
0.072(0.282)
P4(3)
a=61.59 b=61.59
c=91.88 α=90.00
=90.00 γ=90.00
The numbers in parentheses refers to the last (highest) resolution shell. bRmerge =hi|Ihi-<Ih>|/h,i Ihi, where Ihi is the ith
observation of the reflection h, while <Ih> is its mean intensity
a
Table 2: Refinement Statistics
PDB CTD1
PDB CTD2
PDB CTD3
48-2.2
48,564
0.236
0.291
0.006
20-2.6
8,941
Rfactor§
Rfree#
Mean Bond length deviation
50-2.0
15,110
0.238
0.269
0.005
0.204
0.256
0.009
PDB
NTD1
50-1.3
60,751
0.210
0.250
0.008
Mean Bond angle deviation
1.305
1.318
1.176
1.235
94.2
91.6
89.8
88.6
5.8
7.6
10.2
10.4
-
0.6
-
0.5
-
0.2
-
0.5
x
x
0.05
x
Resolution Range (Å)
Number of reflections
Ramachandran statistics
Residues in most favored
regions (%)
Residues in additional
allowed regions (%)
Residues in generously
allowed regions (%)
Residues in disallowed (poor
density) regions (%)
Overall G factor*
§
Rfactor = ||Fobs| - |Fcalc|| /  |Fobs|.
#
Rfree# was calculated with 10% of reflections excluded from the whole refinement procedure.
**G factor is the overall measure of structure quality from PROCHECK (44).
Structure-sequence relationship in CTD. The amino acid sequence of IBV-CTD (Gray
strain) is shown with conserved residues indicated in red and residues that are different in
the Beaudette strain indicated above the corresponding residue in the sequence. The
predicted secondary structure for SARS C-terminal domain (249-380) is superimposed on
observed secondary structure for IBV-CTD shown in red helices green strands and blue
loop regions. The residues involved in the dimer-dimer interactions are shaded with
purple boxes for type S interaction (pH 4.5 and 8.5, CTD1 and CTD2 crystals),
underlined with dark blue lines for type L interactions (pH 8.5, CTD2 crystals), and red
lines for type F interaction (in CTD3 crystals). The surface accessibility is indicated by a
bar at the bottom following a color scheme: totally accessible in white) to buried in dark
blue. Experimental B-factors of individual residues are indicated on a scale from low
(“b” text) to high (“B” text)