Table 1. Comparison of the relative oligomer distribution of CitAP-BsLA samples with (+) and without (−) 1 mM sodium citrate derived from analytical ultracentrifugation (AUC) and small-angle X-ray scattering (SAXS) data obtained for CitAP-BsLA at low concentration (0.5 mg/ml).
relative oligomer distribution |
||||
---|---|---|---|---|
AUC$,§ | SAXS& | |||
− | + | − | + | |
[%] | [%] | [%] | [%] | |
Monomer | 73 | 85 | 73 | 86 |
Dimer | 23 | 12 | 27 | 14 |
>Dimer | 4 | 3 | n.d | n.d |
$For AUC experiments, the relative oligomer distribution was estimated using Bayesian statistics assuming the presence of discrete species of known molecular mass. &From SAXS experiments the average molecular mass was determined, which corresponds directly to the average molecular mass of a population between monomer and dimer with known molecular mass. The molecular mass was determined from the concentration normalized forward scattering and the excluded volume multiplied by the protein density, and the average molecular mass is given. Theoretical molecular mass: monomer: 38.5 kDa, dimer: 77 kDa; §Values represent the mean of two independent sedimentation velocity runs, with an experimental error below 5%.