Analysis of the Interplay among Charge, Hydration and Shape of Proteins through the Modeling of their CZE Mobility Data

PIAGGIO, MARÍA VIRGINIA; PEIROTTI, MARTA BEATRIZ; DEIBER, JULIO ALCIDES

ELECTROPHORESIS

WILEY-VCH Verlag GmbH & Co.

Lugar: Weinheim; Año: 2008

0173-0835

Electrophorectic mobility data of four proteins are analyzed and interpreted through a physicochemical CZE model, which provides estimates of quantities like equivalent hydrodynamic radius (size), effective charge number, shape orientation factor, hydration, actual pK values of ionizing groups, and pH near molecule, among others. Protein friction coefficients are simulated through the creeping flow theory of prolate spheroidal particles. The modeling of the effective electrophoretic mobility of proteins requires consideration of hydrodynamic size and shape coupled to hydration and effective charge. The model proposed predicts native protein hydrations within the range of values obtained experimentally from other techniques. Therefore this model provides consistently other physicochemical properties like average friction and diffusion coefficients and packing fractal dimension. As the pH varies from native conditions to those that are denaturing the protein, hydration and packing fractal dimension change substantially. Needs for further research are also discussed and proposed.