A single layer of about 5 to 25 nm in thickness, comprised of identical proteins (glycoproteins) surrounding the cell of many bacteria and archaea
“S” in S layer stands for “surface”, thus S layer is essentially the surface layer surrounding the cells of different bacterial and archaean species.
The various functions of S layer are:
- mechanical stabilization
- resistance to low pH
- protection from bacteriophages and phagocytic cells
- adhesion site for exoproteins