Application to SMC protein from B. subtilis. In the sections above, we showed how S of the SMC protein from B. subtilis was determined to be 6.3 S from glycerol gradient sedimentation, and Rs was 10.3 nm, from gel filtration. Putting these values in Eq. 7.1b, we find that the molecular weight of SMC protein from B. subtilis is 273,000 Da. From the amino acid sequence, we know that the molecular weight of one SMC protein from B. subtilis subunit is 135,000 Da. The Siegel–Monte analysis finds that the SMC protein from B. subtilis molecule is a dimer.

Knowing that SMC protein from B. subtilis is a dimer with molecular weight 270,000 Da, we can now determine its Smax/S. Smax is 15.1 (Eq. 4.3b) so Smax/S is 2.4. The SMC protein from B. subtilis molecule is thus expected to be highly elongated. EM (see below) confirmed this prediction.