Saposin Lipid Nanoparticles: A Highly Versatile and Modular Tool for Membrane Protein Research

Flayhan A, Mertens H, Ural-Blimke Y, Martinez Molledo M, Svergun D, Löw C, Structure 26(2):345-355.e5 (2018) DOI

SASDC27 – Saposin nanoparticle (SapNP) SapA:DOPC

MWexperimental 33 kDa
MWexpected 28 kDa
VPorod 96 nm3
log I(s) 4.02×104 4.02×103 4.02×102 4.02×101
saposin-a 1,2-dioleoyl-sn-glycero-3-phosphocholine small angle scattering data  s, nm-1
ln I(s)
saposin-a 1,2-dioleoyl-sn-glycero-3-phosphocholine Guinier plot ln 4.03×104 Rg: 4.1 nm 0 (4.1 nm)-2 s2
saposin-a 1,2-dioleoyl-sn-glycero-3-phosphocholine Kratky plot 1.104 0 3 sRg
saposin-a 1,2-dioleoyl-sn-glycero-3-phosphocholine pair distance distribution function Rg: 4 nm 0 Dmax: 11.5 nm

Experimental data validation

Fits and models

log I(s)
 s, nm-1
saposin-a 1,2-dioleoyl-sn-glycero-3-phosphocholine DAMMIF model
Synchrotron SAXS data from solutions of Saposin nanoparticle (SapNP) SapA:DOPC in PBS, pH 7.4 were collected on the P12 camera at the PETRA III storage ring (Hamburg, Germany) using a Pilatus 2M detector at a sample-detector distance of 3.1 m and at a wavelength of λ = 0.124 nm , the range of momentum transfer 0.100 < s < 4.600 nm-1 was covered (l(s) vs s, where s = 4πsinθ/λ, and 2θ is the scattering angle). at 10°C. 20 successive 0.050 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 concentrations were extrapolated to infinite dilution and merged with the higher concentration data to yield the final composite scattering curve.

saposin-a (sapA)
Mol. type   Protein
Organism   Homo sapiens
Olig. state   Monomer
Mon. MW   9.1 kDa
UniProt   P07602 (60-140)
Sequence   FASTA
1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC)
Mol. type   Other
Organism   Synthetic compound
Olig. state   Other
Mon. MW   0.8 kDa