TABLE 3.

Cell wall-located proteins of B. subtilis 168^a

Protein	Function or similarity	Export signalb	SPase	Retention Signalc	Found in mediumd
Hag	Flagellin protein	−	−	−	Y
LytB	Modifier protein of autolysin LytC	Sec	SPase I	CWB	N
LytC	N-Acetylmuramoyl-l-alanine amidase	Sec	SPase I	CWB	N
WapA	Cell wall-associated protein precursor	RR	SPase I	CWB	Y
WprA	Cell wall-associated protein precursor	RR	SPase I	−	Y
YqgA	Similar to unknown proteins of B. subtilis	Sec	SPase I	−	N
YwsB	Similar to unknown proteins of B. subtilis	Sec	SPase I	−	N

^aAll listed cell wall-located proteins were identified by 2D PAGE and subsequent MALDI-TOF mass spectrometry and/or N-terminal amino acid sequencing as described by Antelmann et al. (6). Putative signal peptides, SPase I cleavage sites, and cell wall-binding domains were predicted as described by Tjalsma et al. (129). −, absence of known signal peptides, SPase I cleavage sites, or cell wall-binding proteins.

^bIdentified transient export signals are Sec-type signal peptides (Sec) and RR-type signal peptides (RR).

^cIdentified retention signals present in the mature part of the protein after processing by specific SPases are cell wall-binding domains (CWB).

^dThe presence (Y) or absence (N) of a particular protein of the cell wall proteome in the growth medium is indicated.