Influence of detergent additives on mobility of native and subviral rhinovirus particles in capillary electrophoresis

The electrophoretic properties of two human rhinovirus (HRV) serotypes, HRV2 and HRV14, their subviral particles, and their capsid proteins were investigated by CE using borate buffer, pH 8.3, as BGE and three different detergents as additives. In addition, the influence of modification of the capsid with an amine reactive fluorescent dye, Cy3.5, on migration in the electric field was assessed. We found that the reproducibility of the electrophoretic results was decisively dependent on the presence of the detergents above their respective CMC. As compared to the strong ionic detergent SDS, the nonionic, mild detergent dodecylpoly(ethyleneglycol ether) (D-PEG) efficiently and reproducibly resolved both, native viruses as well as subviral particles. Most of the analytes behaved as expected except native HRV2; this serotype showed a dramatically higher anionic mobility in SDS than in D-PEG. Additionally, its mobility decreased when each positive charge contributed from a lysine at the capsid surface was substituted by four negative charges upon derivatization with Cy3.5. We discuss the possibility that this effect is caused by differences in number and in arrangement of exposed lysines in the two serotypes leading to differences in the amount of bound SDS micelles.