Dynapro dls

DLS was carried out using a 384-well plate DynaPro DLS instrument (Wyatt Technology, Santa Barbara, California) equipped with a 830-nm laser and digital autocorrelator. 35 μL of sample was loaded into each well and the plate was spun at 2000 rpm for 30 s to remove any air bubbles prior to measurement at 20 °C or 25 °C, respectively. The z-average translational diffusion coefficient was determined from cumulant analysis of the autocorrelation function^{61 (link)}, and modeled as $$D_z(c_{\mathit{tot}})=\left(1+k_D{M}_1{c}_{\mathit{tot}}\right)\frac{{\sum }_i{c}_i{M}_i^2{D}_i}{{\sum }_i{c}_i{M}_i^2}$$ using species’ molar concentrations as predicted from sample composition and mass action law (Eq. 17), with species’ diffusion coefficients D_j = s_jRT/M_j(1-vρ) and approximating nonideality with a single average nonideality coefficient and total protein weight concentration $w_{\mathit{tot}}=M_1{c}_{\mathit{tot}}$ .