Table 1 SAXS data-collection and scattering-derived parameters

Data-collection parameters

Instrument

ESRF BM29

Beam Geometry

0.7 mm ×0.7 mm at sample

Wavelength (nm)

0.099

q range (nm ⁻¹)

0.05-4.95

Exposure time

1 s per frame

Concentration, β-amylase

5.5 mg/mL

Concentration, Tobacco Mosaic Virus

26 mg/mL

Temperature (K)

293

Structural Parameters, β-amylase

Exposure time

1 s

10 s (standard)

5 min

30 min

I ₀ (cm ⁻¹) [from Guinier]

0.135 ± 0.001

0.135 ± 0.001

0.133 ± 0.1

0.142 ± 0.001

R _g (nm) [from Guinier]

4.14 ± 0.06

4.14 ± 0.06

4.16 ± 0.06

4.35 ± 0.13

I ₀ (cm ⁻¹) [from P(r)]

0.134

0.135

0.135

0.132

R _g (nm) [from P(r)]

4.09

4.10

4.12

4.22

D _max (nm)

1.10

1.13

1.20

1.30

Porod volume estimate (nm ³)

267

267

266

283

Structural Parameters, Tobacco Mosaic Virus

Exposure time

1 s

10 s (standard)

5 min

30 min

I ₀ (cm ⁻¹ x nm ⁻¹)

0.312 ± 0.003

0.325 ± 0.003

0.330 ± 0.003

0.317 ± 0.003

[from cross-sectional Guinier]

cross-sectional R _g (nm)

6.34

6.40

6.51

6.49

[from cross-sectional Guinier]

I ₀ (cm ⁻¹ x nm ⁻¹)

0.278

0.284

0.289

0.279

[from cross-sectional P(r)]

cross-sectional R _g (nm) [from cross-sectional P(r)]

5.89

5.89

5.88

5.87

cross-sectional D _max (nm)

18.0

18.0

18.0

18.0

Molecular-mass determination, β-amylase

Exposure time

1 s

10 s (standard)

5 min

30 min

Partial specific volume (cm ³ g ⁻¹)

0.724

Contrast (Δ ρ×10¹⁰ cm ⁻²)

3.047

Molecular mass M _r (kDa) [from I ₀]

168 ± 1

170 ± 1

167 ± 1

178 ± 1

Molecular mass M _r (kDa)

157

157

156

166

[from Porod Volume] [64]

Calculated molecular weight according to sequence (kDa)

224

Software employed

Primary data reduction

BM29 online data analysis [65],

pyFAI [66], Primus [64]

1D data processing

PRIMUS

p(r) analysis

GNOM [42]

Form factor fitting

GENFIT [43]

Computation of model intensities

CRYSOL [44]

Computation of volume fractions of mixtures

OLIGOMER [64]