Electrophoretic mobility of sarcoplasmic reticulum vesicles - analytical model includes amino acid residues of A+P+N domain of Ca(2+)-ATPase and charged lipids.

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 Ca(2+)-ATPases embedded in the matrix. The Ca(2+)-ATPase layer both drives and impedes vesicle mobility.

Electrophoretic mobility of sarcoplasmic reticulum vesicles is determined by amino acids of A+P+N domains of Ca2+-ATPase.

Establishing the origin of electrophoretic mobility of sarcoplasmic reticulum (SR) vesicles is the primary goal of this work. It was found that the electrophoretic mobility originates from ionizable amino acids of cytoplasmic domains of the Ca2+-ATPase, the calcium pump of SR. The mobility was measured at pH 4.