Structural basis for osmotic regulation of the DNA binding properties of H-NS proteins.

Qin L, Bdira FB, Sterckx YGJ, Volkov AN, Vreede J, Giachin G, van Schaik P, Ubbink M, Dame RT, Nucleic Acids Res (2020) Europe PMC

SASDGT5 – MvaT (high salt data set)

MvaT(mutant)
MWexperimental 26 kDa
MWexpected 28 kDa
VPorod 50 nm3
log I(s) 7.44×101 7.44×100 7.44×10-1 7.44×10-2
MvaT(mutant) small angle scattering data  s, nm-1
ln I(s)
MvaT(mutant) Guinier plot ln 7.45×101 Rg: 3.8 nm 0 (3.8 nm)-2 s2
(sRg)2I(s)/I(0)
MvaT(mutant) Kratky plot 1.104 0 √3 sRg
p(r)
MvaT(mutant) pair distance distribution function Rg: 4.0 nm 0 Dmax: 15.8 nm

Data validation

Fits and models

log I(s)
 s, nm-1
MvaT(mutant) OTHER [STATIC IMAGE] model
MvaT(mutant) OTHER model
Synchrotron SAXS data from solutions of MvaT (high salt data set) in 20 mM Bis-Tris 300 mM KCl, pH 6 were collected on the BM29 beam line at the ESRF storage ring (Grenoble, France) using a Pilatus 1M detector at a sample-detector distance of 2.8 m and at a wavelength of λ = 0.099 nm (I(s) vs s, where s = 4πsinθ/λ, and 2θ is the scattering angle). In-line size-exclusion chromatography (SEC) SAS was employed. The SEC parameters were as follows: A 250.00 μl sample at 9.5 mg/ml was injected onto a GE Superdex 75 Increase 10/300 column at 20°C. 3000 successive 1 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 protein employed in the SAS experiment contains three point mutations: K31C, F36D, and M44D. K31C was introduced to introduce a paramagnetic label, while F36D and M44D were introduced to abolish higher-order oligomerisation of the protein.

MvaT(mutant)
Mol. type   Protein
Organism   Pseudomonas aeruginosa
Olig. state   Dimer
Mon. MW   14.1 kDa
 
UniProt   Q9HW86 (1-124)
Sequence   FASTA