Table 1 Primers and endonucleases used in the cloning of the various constructs. Restriction endonuclease cut sites are underlined and the regions of the primers homologous to the gene of interest are in bold.

pAPA'

N-terminal: 5' CCA GAA TTC CAT ATG  ACC GTC GAC CAG GCG GCG GAG C 3'

C-terminal: 5' CCA GGA TCC TTA GTT GGC CCC GTA GAG CTT CTG G 3'

Nde I

Bam HI

AprA catalytic fragment (APA')

pPelAPA'

N-terminal: 5' CCG AAT TCC ATG G CC GTC GCC GTC GAC CAG GCG GCG GAG C 3'

C-terminal: Same as pAPA'

Nco I

APA' with pelB secretion signal

pNusAPA'

N-terminal: 5' G GGC GGG GAC GAA TTG GTC AAT GGC 3'

C-terminal: Same as pAPA'

Blunt end ligation at N-terminus: no digestion required

APA' with NusA solubility tag and His₆ tag

pWApr

N-termnal: 5' CCA GAA TTC CAT ATG GGT CGT AGC GAT GCG TAT ACC 3'

C-terminal: 5' CCA GGA TCC TCA GAC GAC GAT GTC GGC CTG G 3'

Nde I

Bam HI

Mature AprA without pro-peptide