Purification of protein A, an outer membrane component missing in Escherichia coli K-12 ompA mutants.
Outer membrane materials prepared from an Escherichia coli ompA (tolG) strain do not contain one of the major outer membrane proteins found in ompA+ strains. This protein has been purified in high yield from detergent-solubilized cell envelope material prepared from an ompA+ strain by preparative electrophoresis in polyacrylamide gels containing sodium dodecyl sulfate. The purified protein is homogeneous in three electrophoretic systems, contains 2 mol of reducing sugar/mol of peptide and has alanine as the N-terminal amino acid. The amino acid composition is nearly identical to outer membrane protein II or B purified by others from incompletely solubilized cell envelope material. Thus, the fraction of outer membrane protein II or B that is difficult to solubilize is identical with the more readily solubilized fraction.
D000596:Amino Acids / Q000032:analysis; D001426:Bacterial Proteins / Q000302:isolation & purification; D002462:Cell Membrane / Q000032:analysis; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000032:analysis*; D008565:Membrane Proteins / Q000302:isolation & purification; D009154:Mutation
D000596:Amino Acids; D001426:Bacterial Proteins; D008565:Membrane Proteins