Biophysical characterization of the Plasmodium falciparum circumsporozoite protein's N‐terminal domain

Geens R, Stanisich J, Beyens O, D'Hondt S, Thiberge J, Ryckebosch A, Groot A, Magez S, Vertommen D, Amino R, Winter H, Volkov A, Tompa P, Sterckx Y, Protein Science (2023) DOI

SASDRF8 – Plasmodium falciparum circumsporozoite protein N-terminal domain at pH 6.6

Circumsporozoite protein
MWexperimental 11 kDa
MWexpected 11 kDa
VPorod 24 nm3
log I(s) 1.27×10-1 1.27×10-2 1.27×10-3 1.27×10-4
Circumsporozoite protein small angle scattering data  s, nm-1
ln I(s)
Circumsporozoite protein Guinier plot ln 1.27×10-1 Rg: 2.3 nm 0 (2.3 nm)-2 s2
(sRg)2I(s)/I(0)
Circumsporozoite protein Kratky plot 1.104 0 3 sRg
p(r)
Circumsporozoite protein pair distance distribution function Rg: 2.5 nm 0 Dmax: 9.1 nm

Data validation


There are no models related to this curve.

Synchrotron SAXS data from solutions of Plasmodium falciparum circumsporozoite protein N-terminal domain in 50 mM MES, 500 mM NaCl, 1 mM TCEP, pH 6.6 were collected on the SWING beam line at SOLEIL (Saint-Aubin, France) using a Eiger 4M detector at a sample-detector distance of 2.0 m and at a wavelength of λ = 0.103 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 50.00 μl sample at 10 mg/ml was injected at a 0.25 ml/min flow rate onto a Shodex KW402.5-4F column at 25°C. 1380 successive 0.990 second frames (10 ms dead time) were collected through the SEC elution. The data were normalized to the intensity of the transmitted beam and radially averaged; the scattering of the solvent-blank was subtracted.

The PfaCSPN sample was concentrated to 10 mg/mL using a centrifugal filter (Amicon Ultra-0.5 3K). Subsequently, a buffer switch was performed using the same device by mixing 50 µL concentrated sample with 450 µL SAXS buffer and concentrating it again to 50 µL. This was repeated five times. Finally, a 50 µL sample was injected onto the SEC column at 10 mg/mL. Data were processed and analysed using the ATSAS package, the online SAXSMoW tool and the RStudio software.

Circumsporozoite protein (CSP)
Mol. type   Protein
Organism   Plasmodium falciparum (isolate NF54)
Olig. state   Monomer
Mon. MW   10.5 kDa
 
UniProt   P19597 (20-101)
Sequence   FASTA