The role of the N-terminal propeptide of the pro-aminopeptidase processing protease: refolding, processing, and enzyme inhibition.
Pro-aminopeptidase processing protease (PA protease) is an extracellular zinc metalloprotease produced by Aeromonas caviae T-64 and it is classified as M04.016 according to the MEROPS database. The precursor of PA protease consists of four regions; a signal peptide, an N-terminal propeptide, a C-terminal propeptide, and the mature PA protease. The in vitro refolding of the intermediate pro-PA protease containing the C-terminal propeptide (MC) was investigated in the presence and absence of the N-terminal propeptide. The results indicate that the noncovalently linked N-terminal propeptide is able to assist in the refolding of MC. In the absence of the N-terminal propeptide, MC is trapped into a folding competent state that is converted into the active form by the addition of the N-terminal propeptide. Moreover, the N-terminal propeptide was found to form a complex with the folded MC and inhibit further processing of MC into the mature PA protease. Inhibitory activity of the purified N-terminal propeptide toward mature PA protease was also observed, and the mode of this inhibition was determined to be a mixed, noncompetitive inhibition with an associated allosteric effect.
Tang
Bing
B
Enzyme Laboratory, Biological Function Division, National Food Research Institute, Tsukuba, 305-8642, Ibaraki, Japan.
Nirasawa
Satoru
S
Kitaoka
Motomitsu
M
Hayashi
Kiyoshi
K
D000333:Aeromonas / Q000201:enzymology; D001426:Bacterial Proteins; D004591:Electrophoresis, Polyacrylamide Gel; D010450:Endopeptidases / Q000378:metabolism*; D011480:Protease Inhibitors; D017510:Protein Folding; D011499:Protein Processing, Post-Translational
D001426:Bacterial Proteins; D011480:Protease Inhibitors; D010450:Endopeptidases; C121413:PA protease protein, Aeromonas