MMCalc: Theoretical molecular mass calculated from amino acid sequence. MMExp: Experimentally based molecular mass calculated from the scattering intensity extrapolated at zero angles I(0). O.S: Oligomeric state, as determined by comparison between the MMCalc and the MMExp. RG*: Radius of gyration, estimated from the Guinier plots. RG**: Radius of gyration, estimated using the program GNOM. V: volume of the envelope calculated by ab initio modelling. ChiExp: discrepancy between the experimental SAXS profile and the fit for each model calculated by the program GASBOR. The ratios of the Molecular Masses and of the volumes between different constructs are given in the last two lines.