Domain crossover in the reductase subunit of NADPH-dependent assimilatory sulfite reductase.

Walia N Murray DT, Garg Y, He H, Weiss KL, Nagy G, Elizabeth Stroupe M, J Struct Biol 215(4):108028 (2023) Europe PMC

SASDS52 – Sulfite reductase crosslinked dodecamer

Sulfite reductase [NADPH] hemoprotein beta-component
Sulfite reductase [NADPH] flavoprotein alpha-component (E121C, C162T, C552S, N556C)

MW^experimental	873	kDa
MW^expected	822	kDa
V^Porod	1170	nm³

log I(s) 2.41×10⁰ 2.41×10^-1 2.41×10^-2 2.41×10^-3

Sulfite reductase [NADPH] hemoprotein beta-component Sulfite reductase [NADPH] flavoprotein alpha-component (E121C, C162T, C552S, N556C) 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 (E121C, C162T, C552S, N556C) Guinier plot

ln 2.41×10⁰ R_g: 10.3 nm 0 (10.3 nm)^-2 s²

(sR_g)²I(s)/I(0)

Sulfite reductase [NADPH] hemoprotein beta-component Sulfite reductase [NADPH] flavoprotein alpha-component (E121C, C162T, C552S, N556C) Kratky plot

1.104 0 √3 sR_g

p(r)	R_g: 10.4 nm 0 D_max: 31 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

0.853
0.732

Worse

Better

Fits and models

log I(s)	s, nm^-1
+3 Δ/σ -3	s, nm^-1

SANS data from solutions of sulfite reductase crosslinked dodecamer in 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 sample is a dodecameric oligomer containing a His-tagged sulfite reductase flavoprotein crosslinked octamer and four copies of hemoprotein. Two instrument configurations were used: 4 m sample-to-detector distance with 1.0 nm wavelength band, 2.5 m sample-to-detector distance with 0.25 nm wavelength band. Sample concentration: 3 mg/mL. Neutron exposure time: 1 hour / instrument configuration. Sample temperature: 8°C.

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

UniProt		P17846
Sequence		FASTA

Sulfite reductase [NADPH] flavoprotein alpha-component (E121C, C162T, C552S, N556C)
Mol. type		Protein
Organism		Escherichia coli (strain K12)
Olig. state		Octamer
Mon. MW		70.7 kDa

UniProt		P38038 (1-599)
Sequence		FASTA