Figure 2

Multiple amino acid sequence alignment of AprX-SK37 with selected Apr-related subtilisin-like serine proteases. Sequence aligned: subtilisin E (aprE-subtilis) (P04189) from Bacillus subtilis; Subtilisin J (aprJ-stearo) (P29142) from B. stearothermophilus; subtilisin NAT (aprN-natto) (P35835) from B. subtilis subsp. "natto"; subtilisin ALP (aprQ-APL) (Q45523) from Bacillus sp. GN; subtilisin Sendai (aprS-sendi) (Q45522) from Bacillus sp. G-825-6; AprX (aprX-subtilis) (O31788) from B. subtilis; AprX (aprX-amylo) (A7Z4Z4) from B. amyloliquefaciens; AprX (aprX-lichen) (Q65IP4) from B. licheniformis; intracellular alkaline serine protease (aprX-halo) (Q9KBJ7) from B. halodurans; S8A subfamily protease (aprX-pumilus) (A8FDI1) from B. pumilus; alkaline serine protease X (aprX-sk37) from Virgibacillus sp. SK37. Secondary structure elements of the AprE are indicated above the alignment; common structural elements are shown as; rectangular for α-helices, arrow for β-sheet strands, and filled thin bar for calcium binding domain [42]. Identical and similar (>75%) amino acid residues among all enzymes are shaded in black and gray, respectively. Conserved amino acid residues involved in the active side (Asp, His, and Ser) are indicated by asterisks below the alignments. Signal and pro-peptide are marked by a gray-letter and underline, respectively.