The primary structure and structural characteristics of Achromobacter lyticus protease I, a lysine-specific serine protease.
The complete amino acid sequence of Achromobacter lyticus protease I (EC 3.4.21.50), which specifically hydrolyzes lysyl peptide bonds, has been established. This has been achieved by sequence analysis of the reduced and S-carboxymethylated protease and of peptides obtained by enzymatic digestion with Achromobacter protease I itself and Staphylococcus aureus V8 protease and by chemical cleavage with cyanogen bromide. The protease consists of 268 residues with three disulfide bonds, which have been assigned to Cys6-Cys216, Cys12-Cys80, and Cys36-Cys58. Comparison of the amino acid sequence of Achromobacter protease and other serine proteases of bacterial and mammalian origins has revealed that Achromobacter protease I is a mammalian-type serine protease of which the catalytic triad comprises His57, Asp113, and Ser194. It has also been shown that the protease has 9- and 26-residue extensions of the peptide chain at the N and C termini, respectively, and overall sequence homology is as low as 20% with bovine trypsin. The presence of a disulfide bridge between the N-terminal extension Cys6 and Cys216 close to the putative active site in the C-terminal region is thought to be responsible for the generation of maximal proteolytic function in the pH range 8.5-10.7 and enhanced stability to denaturation.
Tsunasawa
S
S
Institute for Protein Research, Osaka University, Japan.
Masaki
T
T
Hirose
M
M
Soejima
M
M
Sakiyama
F
F
D000421:Alcaligenes / Q000201:enzymology*; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000648:ultrastructure; D008239:Lysine; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000032:analysis; D012697:Serine Endopeptidases / Q000235:genetics*; D013379:Substrate Specificity
D001426:Bacterial Proteins; D010446:Peptide Fragments; D012697:Serine Endopeptidases; C036813:lysyl endopeptidase; D008239:Lysine