Neutron scattering maps the higher-order assembly of NADPH-dependent assimilatory sulfite reductase.

Murray DT, Walia N, Weiss KL, Stanley CB, Randolph PS, Nagy G, Stroupe ME, Biophys J (2022) Europe PMC

SASDMQ8 – Reconstituted sulfite reductase dodecamer with partially deuterated hemoprotein in 86% D2O

Sulfite reductase [NADPH] hemoprotein beta-component
Sulfite reductase [NADPH] flavoprotein alpha-component (His-tagged)

MW^experimental	839	kDa
MW^expected	821	kDa
V^Porod	460	nm³

log I(s) 8.36×10^-1 8.36×10^-2 8.36×10^-3 8.36×10^-4

Sulfite reductase [NADPH] hemoprotein beta-component Sulfite reductase [NADPH] flavoprotein alpha-component (His-tagged) small angle scattering data

s, nm^-1

Log plot Log-Log plot

ln I(s)

Sulfite reductase [NADPH] hemoprotein beta-component Sulfite reductase [NADPH] flavoprotein alpha-component (His-tagged) Guinier plot

ln 8.36×10^-1 R_g: 6.8 nm 0 (6.8 nm)^-2 s²

(sR_g)²I(s)/I(0)

Sulfite reductase [NADPH] hemoprotein beta-component Sulfite reductase [NADPH] flavoprotein alpha-component (His-tagged) Kratky plot

1.104 0 √3 sR_g

p(r)	R_g: 7.3 nm 0 D_max: 22 nm

Data validation

Experimental data range

p(r) fit to data

Metric

Value

s_min D_max / π

0.8

N_Shannon

Worse

Better

Metric

Value

p_cormap

χ²

0.519
0.701

Worse

Better

Fits and models

log I(s)	s, nm^-1
+3 Δ/σ -3	s, nm^-1

SANS data from solutions of reconstituted sulfite reductase dodecamer with partially deuterated hemoprotein in 86% D2O, 50 mM KPi, 100 mM NaCl, 1 mM EDTA, pH 7.8 were collected using the EQ-SANS (BL-6) spallation neutron source (Oak Ridge, Tennessee, USA). This reconstituted sample is a dodecamer of His-tagged sulfite reductase flavoprotein octamer and four copies of partially deuterated hemoprotein. Three instrument configurations were used: 9 m sample-to-detector distance with 1.5 nm wavelength band, 4 m sample-to-detector distance with 0.6 nm wavelength band, and 1.3 m sample-to-detector distance with 0.4 nm wavelength band. Sample concentration: 11.2 mg/mL. Neutron exposure time: 3 hours / instrument configuration. Sample temperature: 8°C.

X-ray Exposure time = UNKNOWN. Number of frames = UNKNOWN

Sulfite reductase [NADPH] hemoprotein beta-component (SiRHP)
Mol. type		Protein
Organism		Escherichia coli (strain K12)
Olig. state		Tetramer
Mon. MW		64.0 kDa

UniProt		P17846 (1-570)
Sequence		FASTA

Sulfite reductase [NADPH] flavoprotein alpha-component (His-tagged) (His-tagged SiRFP)
Mol. type		Protein
Organism		Escherichia coli (strain K12)
Olig. state		Octamer
Mon. MW		70.7 kDa

UniProt		P38038 (1-590)
Sequence		FASTA