Conformational multiplicity of bacterial ferric binding protein revealed by small angle x-ray scattering and molecular dynamics calculations

Liu G, Ekmen E, Jalalypour F, Mertens H, Jeffries C, Svergun D, Atilgan A, Atilgan C, Sayers Z, The Journal of Chemical Physics 158(8) (2023) DOI

SASDWP7 – Wild type ferric binding protein (FbpA) in holo (with Fe) form in low ionic strength (LIS) buffer (1/10 PBS)

Iron-utilization periplasmic protein
MWexperimental 31 kDa
MWexpected 34 kDa
VPorod 29 nm3
log I(s) 1.85×10-2 1.85×10-3 1.85×10-4 1.85×10-5
Iron-utilization periplasmic protein small angle scattering data  s, nm-1
ln I(s)
Iron-utilization periplasmic protein Guinier plot ln 1.86×10-2 Rg: 2 nm 0 (2 nm)-2 s2
(sRg)2I(s)/I(0)
Iron-utilization periplasmic protein Kratky plot 1.104 0 √3 sRg
p(r)
Iron-utilization periplasmic protein pair distance distribution function Rg: 2.0 nm 0 Dmax: 6.1 nm

Data validation

Fits and models

log I(s)
 s, nm-1
Iron-utilization periplasmic protein DAMMIN model
Synchrotron SAXS data from solutions of Wild type ferric binding protein (FbpA) in holo (with Fe) form in low ionic strength (LIS) buffer (1/10 PBS) in 1 mM Na2HPO4.7H2O, 0.18 mM KH2PO4, 13.7 mM NaCl, 0.27 mM KCl, 5%v/v Glycerol, pH 7.4 were collected on the EMBL P12 beam line at the PETRA III storage ring (DESY; Hamburg, Germany) using a Pilatus 6M detector at a sample-detector distance of 3 m and at a wavelength of λ = 0.124 nm (I(s) vs s, where s = 4πsinθ/λ, and 2θ is the scattering angle). One solute concentration of 3.00 mg/ml was measured at 4°C. 40 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.

Iron-utilization periplasmic protein (FBPA_HAEIN)
Mol. type   Protein
Organism   Haemophilus influenzae
Olig. state   Monomer
Mon. MW   33.8 kDa
 
UniProt   P35755 (23-332)
Sequence   FASTA