BIO-BEADS - AN EFFICIENT STRATEGY FOR 2-DIMENSIONAL CRYSTALLIZATION OF MEMBRANE-PROTEINS

This work establishes the potential of Bio-Beads as a simple alternati ve to conventional dialysis for removing detergent and for obtaining 2 D crystals of integral membrane proteins useful for structure analysis by electron crystallography. Kinetic and equilibrium aspects of remov al of different detergents by adsorption onto hydrophobic Bio-Beads SM 2 leave been systematically investigated and extended to 2D crystalliz ation of different prototypic membrane proteins, including: (a) Ca2+ A TPase from sarcoplasmic reticulum; (b) melibiose permease from Escheri chia coli; (c) cytochrome b(6)f from Chlamydomonas reinhardtii. Differ ent crystals could be produced from all protein preparations, with opt ical diffraction down to 20-25 Angstrom in negative stain, (C) 1997 Ac ademic Press.