Combination of SAXS and Protein Painting Discloses the Three-Dimensional Organization of the Bacterial Cysteine Synthase Complex, a Potential Target for Enhancers of Antibiotic Action.

Rosa B, Marchetti M, Paredi G, Amenitsch H Franko N, Benoni R, Giabbai B, De Marino MG, Mozzarelli A, Ronda L, Storici P, Campanini B, Bettati S, Int J Mol Sci 20(20) (2019) Europe PMC

SASDGX6 – Cysteine synthase/Serine acetyltransferase complex

Cysteine synthase A (4-mer)
Serine acetyltransferase (6-mer)
MWexperimental 303 kDa
MWexpected 319 kDa
VPorod 457 nm3
log I(s) 2.69×101 2.69×100 2.69×10-1 2.69×10-2
Cysteine synthase A (4-mer) Serine acetyltransferase (6-mer) small angle scattering data  s, nm-1
ln I(s)
Cysteine synthase A (4-mer) Serine acetyltransferase (6-mer) Guinier plot ln 2.70×101 Rg: 6.1 nm 0 (6.1 nm)-2 s2
(sRg)2I(s)/I(0)
Cysteine synthase A (4-mer) Serine acetyltransferase (6-mer) Kratky plot 1.104 0 3 sRg
p(r)
Cysteine synthase A (4-mer) Serine acetyltransferase (6-mer) pair distance distribution function Rg: 6.6 nm 0 Dmax: 22 nm

Data validation


Fits and models


log I(s)
 s, nm-1
Cysteine synthase A (4-mer) Serine acetyltransferase (6-mer) DAMMIF model

Synchrotron SAXS data from solutions of the cysteine synthase complex in 20 mM sodium phosphate, 85 mM NaCl, 2 mM EDTA, 10 mM 2-MCE, pH 7.5 were collected on the Austrian SAXS beamline 5.2L beam line at the ELETTRA - Sincrotrone Trieste storage ring (Trieste, Italy) using a Dectris / Pilatus3 1M detector at a sample-detector distance of 1.2 m and at a wavelength of λ = 0.154 nm (I(s) vs s, where s = 4πsinθ/λ, and 2θ is the scattering angle). Solute concentrations ranging between 0.5 and 1.5 mg/ml were measured at 20°C. 12 successive 10 second frames were collected. The data were normalized to the intensity of the transmitted beam and radially averaged; the scattering of the solvent-blank was subtracted. The low angle data collected at lower concentration were merged with the highest concentration high angle data to yield the final composite scattering curve.

Cysteine synthase A (4-mer) (CysK)
Mol. type   Protein
Organism   Escherichia coli
Olig. state   Tetramer
Mon. MW   35.7 kDa
 
UniProt   P0ABK5 (1-323)
Sequence   FASTA
 
Serine acetyltransferase (6-mer) (CysE)
Mol. type   Protein
Organism   Escherichia coli
Olig. state   Hexamer
Mon. MW   29.4 kDa
 
UniProt   P0A9D4 (2-273)
Sequence   FASTA