Parallel axes theorem

Further Rq analyses can be carried out to investigate conformational changes in the particle, binding equilibria between different particles, and comparisons with known macromolecular crystal structures. The Parallel Axes Theorem is useful to study oligomer formation or the fragmentation of a particle, since it yields the separation A between the two subunits in the object of interest ... 

This expression is identical with the Parallel Axes Theorem above, even though the two components have been distinguished by contrast variation and not by chemical separation into separate entities [48]. This identity is readily shown by equating R and Rqb in the Parallel Axes Theorem with the Rq values in the Stuhrmann plot at Ap values that correspond to the matchout of components B and A respectively, i.e. 

In addition, A was obtained from the Parallel Axes Theorem (Section 2.6) using individual Rq data for the monolabelled and bilabelled multimers [191,192]. The a a2, CT-jS and distances had to be obtained from the use of separate... 

Deuteration was also used to investigate the dimer of methionyl-tRNA synthetase [196], Mixture of the deuterated and protonated dimers DD and HH causes hydrid HD dimers to be formed through reversible dissociation. The equilibrium mixture of HH, DD and HD dimers is polydisperse in a //(O) matchpoint graph (cf. ferritin in Section 4.3.1) from which the amount of HD present is calculated. Comparison with the Rq values measured as a function of percentage H20 gave the of monomer and the Parallel Axes Theorem gave the distance between the monomers. 

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