Electrophoretic mobility of sarcoplasmic reticulum vesicles — Analytical model includes amino acid residues of A + P + N domain of Ca2+-ATPase and charged lipids
| Autor: | Laura Elizabeth Satterfield, Pavel Smejtek, Robert Campbell Word |
|---|---|
| Rok vydání: | 2014 |
| Předmět: |
Electrophoresis
Calcium pump Lipid Bilayers Static Electricity Biophysics Analytical chemistry Sarcoplasmic reticulum vesicle Calcium-Transporting ATPases Electrolyte Biochemistry Matrix (chemical analysis) Electrophoretic mobility Animals Surface layer pH dependence Chemistry Endoplasmic reticulum Vesicle Cell Biology Hydrogen-Ion Concentration Calcium pump layer Kinetics Sarcoplasmic Reticulum Membrane Models Chemical Rabbits Ca2+-ATPase |
| Zdroj: | Biochimica et Biophysica Acta (BBA) - Biomembranes. 1838:766-775 |
| ISSN: | 0005-2736 |
| DOI: | 10.1016/j.bbamem.2013.09.019 |
| Popis: | This work is an experimental and theoretical study of electrostatic and hydrodynamic properties of the surface of sarcoplasmic reticulum (SR) membrane using particle electrophoresis. The essential structural components of SR membrane include a lipid matrix and a dense layer of Ca2 +-ATPases embedded in the matrix. The Ca2 +-ATPase layer both drives and impedes vesicle mobility. To analyze the experimental mobility data, obtained at pH 4.0, 4.7, 5.0, 6.0, 7.5, and 9.0 in 0.1 M monovalent (1:1) electrolyte, an analytical solution for the vesicle mobility and electroosmotic flow velocity distribution was obtained by solving the Poisson–Boltzmann and the Navier–Stokes–Brinkman equations. The electrophoretic mobility model includes two sets of charges that represent: (a) charged lipids of the lipid matrix of the vesicle core, and (b) charged amino acid residues of APN domains of Ca2 +-ATPases. APN domains are assumed to form a charged plane displaced from the surface of lipid matrix. The charged plane is embedded in a frictional layer that represents the surface layer of calcium pumps. Electrophoretic mobility is driven by the charged APN domain and by lipid matrix while the surface layer provides hydrodynamic friction. The charge of APN domain is determined by ionized amino acid residues obtained from the amino acid composition of SERCA1a Ca2 +-ATPase. Agreement between the measured and the predicted mobility is evaluated by the weighted sum of mobility deviation squared. This model reproduces the experimental dependence of mobility on pH and predicts that APN domains are located in the upper half of the SR vesicle surface layer. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect