Table 4.

Plasmids used in this work.

Plasmid	Characteristics	Resistance	Reference
pTIL 120	pGhost 9-pepF deleted: 162 b.p. deletion including the active site	Ery	Nardi et al. (1997)
pSEC1	expression under PnisA encodes SPUsp:NucB	Cm	Chatel et al. (2001)
pILN13	allows switch to low copy number	Ery	Renault et al. (1996)
pET28	conceived for heterologous protein production	Km	Novagen