RR02-Rec Monomer (Less Than 5Mg/Ml)

RR02-Rec Monomer (less than 5mg/ml)

Figure Above: All experiments were carried out using the same batch of protein that was concentrated to give different protein concentrations (estimated from the extinction coefficient 0.188 M-1 cm-1). A DynaPro-801 TC molecular sizing instrument was used for the Dynamic light scattering experiments (DLS). The instrument was blanked prior to each of the three experiments as described by the manufactures. Briefly, the instrument was initially blanked using distilled water to active a steady baseline, this is followed by a second blank, this time using the buffer, which the protein is suspended. The final blanking step involved injection of the protein. All solutions were filtered through a 20-micron filter before entering the instruments cuvette.

In the first image above the figure on the right represents the molecular weight of the protein in solution with error bars showing the differences in the estimated molecular weight. This graphical representation is derived from the figures in the lower table. In this table the important figures to notice (from right to left) are, the SOS error, the values in this experiment show background noise, however the Baseline error of approx 1.0 shows the sample to have a narrow monomodal size distribution (there is only one species (protein) of the same size present in solution). Whilst the Est. MW, gives an estimate of the molecular weight of your sample and the PolyD (polydispersity) of the sample gives an indication of the number of species (if more than one is present) found within the sample.

With the concentration of the protein maintained at bellow 5mg/ml-1 we see that the average estimated weight of the protein is 15 kDa.

RR02-Rec Dimer (10mg/ml)

In this experiment the SOS error, the values are smaller than in the previous experiment but they still show background noise within the experiment, the values for the Baseline error (approx 1.0) are excellent, again showing the sample to contain only a single species.

With the concentration of the protein maintained at 10mg/ml-1 we see that the average estimated weight of the protein is 31 kDa this value is within experimental error of the expected molecular weight of the dimer (approx 28 kDa).

RR02-Rec Higher Order Oligomers (Greater than 15mg/ml)

In this experiment the SOS error, the values are much smaller than in the previous two experiments showing negligible error with low background noise, the values for the Baseline error (approx 1.0) are again excellent, showing the sample to contain only a single species.

With the concentration of the protein maintained at above 15mg/ml-1 we see that the average estimated weight of the protein is 79 kDa this value is within experimental error of the expected molecular weight of the higher order oligomer (approx 80 kDa).