Localization of Protein A in the Bacteria

Abstract

Staphylococcus aureus, strain Cowan I, contains 1.7% protein A and its isolated cell walls contain 6.7%. Removal of contaminating cytoplasmic membrane fragments from the cell walls does not decrease the content of protein A. Extraction of cell walls with trichloroacetic acid releases teichoic acid but not protein A. Extractions with high concentrations of LiCl do not remove protein A. Only bacteriolytic enzymes can release the protein. Protein A isolated from bacteria after lysozyme digestion contains peptidoglycan constituents. More effective bacteriolytic enzymes such as lysostaphin release peptidoglycan fragments from this protein A preparation. We conclude from these results that protein A is a cell wall component of S. aureus and is covalently linked to the peptidoglycan structure. Copyright © 1972, Wiley Blackwell. All rights reserved