Estimation of global structural and transport properties of peptides through the modeling of their CZE mobility data

Abstract

Peptide electrophoretic mobility data are interpreted through a physicochemical CZE model, providing estimates of the equivalent hydrodynamic radius, hydration, effective and total charge numbers, actual ionizing pK, pH-near molecule and electrical permittivity of peptide domain, among other basic properties. In this study, they are used to estimate some peptide global structural properties proposed, providing thus a distinction among different peptides. Therefore, the solvent drag on the peptide is obtained through a characteristic friction power coefficient of the number of amino acid residues, defined from the global chain conformation in solution. As modeling of the effective electrophoretic mobility of peptides is carried out in terms of particle hydrodynamic size and shape coupled to hydration and effective charge, a packing dimension related to chain conformation within the peptide domain may be defined. In addition, the effective and total charge number fractions of peptides provide some clues on the interpretation of chain conformations within the framework of scaling laws. Furthermore, the model estimates transport properties, such as sedimentation, friction and diffusion coefficients. As the relative numbers of ionizing, polar and non-polar amino acid residues vary in peptides, their global structural properties defined here change appreciably. Needs for further research are also discussed.

Towards a continuous adsorption process for the enrichment of ACE-inhibiting peptides from food protein hydrolysates

“…Therefore, batch adsorption isotherms were recorded for Ile-Trp and Trp using the smallest fraction F50. Ile-Trp is the strongest ACE-inhibitor in AAT while Trp is a non-active side product of the hydrolysis, which is comparable in size and polarity [32,33]. Hence, similar adsorption properties can be expected.…”

Determination of electrokinetic and hydrodynamic parameters of proteins by modeling their electrophoretic mobilities through the electrically charged spherical porous particle

“…To improve the prediction of Eq. when polypeptides are considered, the perturbed Linderstrøm‐Lang capillary electrophoresis model (PLLCEM) was proposed , where electrophoretic mobilities of aspherical hard particles (AHPs) were studied in the low charge regime, by defining the shape orientation factor . Here, the friction coefficient is evaluated either from AHP, such as spheroidal particles, or from hydrated chain fractals by defining the chain friction , where g f is the friction fractal dimension and a o is the average radius of N amino acid residues in the amino acid sequence (AAS) evaluated from their van der Waals radii.…”

“…Here, the friction coefficient is evaluated either from AHP, such as spheroidal particles, or from hydrated chain fractals by defining the chain friction , where g f is the friction fractal dimension and a o is the average radius of N amino acid residues in the amino acid sequence (AAS) evaluated from their van der Waals radii. Also in this framework the packing fractal dimension is as defined in . This simple CZE model yields approximate numerical values of useful polypeptide properties, apart from a H , Ω, f, and Z, when chain AAS and molar mass M are known.…”

“…Therefore, in this work and following one , we have the target of analyzing different particles (SPP and SSP) to obtain as main result the particle–solvent friction for different chain conformations. Then this parameter may be interpreted through the “hydrated chain fractal” model (as it was done for the AHP in ) to evaluate the packing and friction fractal dimensions of polypeptide chains, which in turns are crucial to examine polypeptide global conformations and scaling laws at different pH values. These scaling laws relate chain electrophoretic mobility to intrinsic viscosity, diffusion and sedimentation coefficients, and particle permeability in different polypeptide conformational states .…”

Specific ion effects on the electrophoretic mobility of small, highly charged peptides: A modeling study

“…CE offers a simple but very effective way of separating peptides as well as other ionic species and nanoparticles on the basis of their size and charge. In recent years, numerous investigators employing a variety of modeling strategies have analyzed free solution CE mobility data of peptides in an attempt to determine their physicochemical properties and, in some cases, elucidate their structure . Our laboratory has played a part in these studies by developing a coarse‐grained bead modeling methodology (BMM) that partially accounts for the finite extent of peptides in modeling their electrophoretic mobility .…”