Table 1 List of bacterial strains and plasmids used in this study

E. coli DH5α

F^- end A1 gln V44 thi- 1 rec A1 rel A1 gyr A96 deo R nup G Φ80dlac ZΔM15 Δ(lac ZYA-arg F) U169, hsd R17(r _K ^- m _K ⁺ ), λ-

Invitrogen (CA, USA)

E. coli DH10B

F^- end A1 rec A1 gal E15 gal K16 nupG rps L Δlac X74 Φ80lac ZΔM15 ara D139 Δ(ara, leu) 7697 mcr A Δ(mrr-hsd RMS-mcr BC) λ^-

Invitrogen (CA, USA)

E. coli BL21 (DE3)

F^- omp T gal dcm lon hsd S_B (r _B ^- m _B ^- ) λ( DE3 [lacI lac UV5-T7 gene 1 ind 1 sam 7 nin 5])

Novagen (CA, USA)

pUC19

Ap^r ; Cloning vector

Stratagene (CA, USA)

pTZ57R/T

Ap^r; PCR cloning vector

MBI Fermentas (Opelstrasse, Germany)

pET30b

Kn^r; Expression vector; T7 promoter

Novagen (CA, USA)

pSP1

pUC19 harbouring the AS-protease ORF; Ap^r

This study

pTSP1

AS- Protease ORF cloned in pTZ57R/T; Ap^r

This study

pETP1

AS- protease ORF cloned in pET30b; Kn^r

This study