In the case of CoM-CG calculations, our results show that R 1 is dominated by the inter-monomer component (R R-chain 1 ) in the low PEG concentration limit (Fig. ). In the high PEG concentration limit, R R-chain 1 and R T 1 are of similar magnitude. Our results also indicate that there is no exact agreement between AA and CoM-CG for the calculations of R R-chain 1 and R T 1 : both contributions calculated from CoM-CG are shifted toward lower values as compared to AA (Fig. ). Such offsets on R R-chain 1 and R T 1 can be explained by the comparatively larger typical distances between spin carriers under the CoM-CG representation as compared with the AA representation, as indicated by radial distribution functions g(r) (Fig. ). Such increased typical distance between spin carriers leads to a reduction in the absolute value of the correlation function G, as G depends on the interspecies distances as G ∼ r -6 [Eqs. ], which in turn translates into a reduction of the relaxation rate R 1 [Eq. ( )].