Standard proteins

Darja Ruskule.

SASDA32 – BSA in HEPES

Human Serum Albumin
MWI(0) 64 kDa
VPorod 97 nm3
log I(s) 5.93×101 5.93×100 5.93×10-1 5.93×10-2
Human Serum Albumin small angle scattering data  s, nm-1
ln I(s)
Human Serum Albumin Guinier plot ln 5.93×101 Rg: 2.9 nm 0 (2.9 nm)-2 s2
(sRg)2I(s)/I(0)
Human Serum Albumin Kratky plot 1.104 0 3 sRg
p(r)
Human Serum Albumin pair distance distribution function Rg: 2.8 nm 0 Dmax: 9.3 nm

Data validation


Fits and models


log I(s)
 s, nm-1
Human Serum Albumin DAMMIF model

log I(s)
 s, nm-1
Human Serum Albumin NONE model

Synchrotron SAXS data from solutions of BSA in HEPES in 50 mM HEPES 50 mM KCl, pH 7.5 were collected on the EMBL X33 beam line at the DORIS III storage ring (Hamburg, Germany) using a Pilatus 1M-W detector at a sample-detector distance of 2.7 m and at a wavelength of λ = 0.15 nm (I(s) vs s, where s = 4πsinθ/λ, and 2θ is the scattering angle). One solute concentration of 25.64 mg/ml was measured at 10°C. Eight successive 15 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.

Bovin Serum Albumin (BSA) is an extremely important protein in Small Angle X-Ray Scattering. It is, in fact, used as standard in order to calculate the molecular weight of other proteins. The reasons why it has been chosen as standard it is because it can be easily stored in its powder form and it is also very well characterised. In solution is present as a monomer-dimer equilibrium, therefore the molecular weight of the standard BSA is not the one of the monomer (68 kDa) but is slightly bigger (72 kDa). The crystal structure of BSA has been solved recently therefore ab initio models can be compared with atomic structure like in this picture.

Tags: X33
Human Serum Albumin (HSA)
Mol. type   Lipid
Organism   Homo sapiens
Olig. state   Monomer
Chemical formula
 
PDB ID   3V03