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Data are presented demonstrating that absorbance detection can be used during high-speed sedimentation velocity analytical ultracentrifugation (hs-SV-AUC) experiments to characterize the size distribution of adeno-associated virus (AAV) drug products accurately. Advantages and limitations of being able to use this detector in this specific type of SV-AUC experiment are discussed., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

The diffusion interaction parameter ( k D ) has been demonstrated to be a high-throughput technique for characterizing interactions between proteins in solution. k D reflects both attractive and repulsive interactions, including long-ranged electrostatic repulsions. Here, we plot the mutual diffusion coefficient ( D m ) as a function of the experimentally determined Debye-Hückel-Henry surface charge ( Z DHH ) for seven human monoclonal antibodies (mAbs) in 15 mM histidine at pH 6. We find that graphs of D m versus Z DHH intersect at Z DHH , ~ 2.6, independent of protein concentration. The same data plotted as k D versus Z DHH show a transition from net attractive to net repulsive interactions in the same region of the Z DHH intersection point. These data suggest that there is a minimum surface charge necessary on these mAbs needed to overcome attractive interactions., (© The Author(s) 2022. Published by Oxford University Press on behalf of Antibody Therapeutics. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Prions, misfolded proteins that aggregate, cause an array of progressively deteriorating conditions to which, currently, there are no effective treatments. The presently accepted model indicates that the soluble non-prion forms of prion-forming proteins, such as the well-studied SUP35, do not exist in large aggregated molecular complexes. Here, we show using analytical ultracentrifugation with fluorescent detection that the non-prion form of SUP35 exists in a range of discretely sized soluble complexes (19S, 28S, 39S, 57S, and 70S-200S). Similar to the [PSI+] aggregated complexes, each of these [psi-] complexes associates at stoichiometric levels with a large variety of molecular chaperones: HSP70 proteins comprise the major component. Another yeast prion-forming protein, RNQ1 (known to promote the production of the prion SUP35 state), is also present in SUP35 complexes. These results establish that the non-prion SUP35, like its prion form, is predisposed to form large molecular complexes containing chaperones and other prion-forming proteins. These results agree with our previous studies on the huntingtin protein. That the normal forms for aggregation-prone proteins may preexist in large molecular complexes has important ramifications for the progression of diseases involving protein aggregation., (© 2021 Wiley Periodicals LLC.)