FIG. 7.

Diagram to illustrate a hypothesis on the deposition of protein A in the cell wall envelope of S. aureus. The cross wall, a thick layer of newly synthesized peptidoglycan, separates two newly formed daughter cells and is indicated as a green ring structure. Two to four foci of protein A staining (red dots) mark sites for the secretion and deposition of newly synthesized surface protein into murein sacculi. As cells grow and the cross wall expands, surface protein deposition forms a ring-like structure that traverses areas of cell wall synthesis. Once cell wall synthesis and separation as well as surface protein ring formation have been completed, new cross walls and foci of protein A deposition are formed perpendicular to previous planes of division and surface protein anchoring.