Aerolysin is activated by metalloprotease in Aeromonas veronii biovar sobria.
Aeromonas veronii is an opportunistic human pathogen that causes diarrhoea and extraintestinal infections, such as wound infection and septicaemia. An A. veronii protease (AVP) from a biovar sobria strain, AeG1, was partially purified and characterized. Mature AVP hydrolysed casein but not elastin, and protease activity was inhibited by metalloprotease inhibitors. Nucleotide sequence analysis showed that AVP belongs to the thermolysin family of proteases. An AVP-deficient mutant was constructed to investigate the role of AVP in aerolysin activation. Western blot analysis using anti-aerolysin antisera revealed that proaerolysin (52 kDa) in the AVP-deficient mutant was not completely activated to mature aerolysin (47 kDa) as seen in the wild-type strain. The AVP-deficient mutant showed lower cytotoxic and haemolytic activities than wild type. AVP and proaerolysin had no haemolytic activity; however, activity appeared after incubating both proteins. Taken together, these results suggested that AVP plays an indirect role in virulence through activating aerolysin, which is an essential step for cytotoxic activity.
Song
Tianyan
T
Division of Bacterial Pathogenesis, Department of Microbiology, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nishihara, Okinawa 903-0215, Japan.
Toma
Claudia
C
Division of Bacterial Pathogenesis, Department of Microbiology, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nishihara, Okinawa 903-0215, Japan.
Nakasone
Noboru
N
Division of Bacterial Pathogenesis, Department of Microbiology, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nishihara, Okinawa 903-0215, Japan.
Iwanaga
Masaaki
M
Division of Bacterial Pathogenesis, Department of Microbiology, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nishihara, Okinawa 903-0215, Japan.
D000333:Aeromonas / Q000378:metabolism* / Q000472:pathogenicity; D000595:Amino Acid Sequence; D000818:Animals; D001427:Bacterial Toxins / Q000096:biosynthesis / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D015153:Blotting, Western; D002460:Cell Line; D003001:Cloning, Molecular; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D045726:Metalloproteases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D052899:Pore Forming Cytotoxic Proteins; D037521:Virulence Factors / Q000378:metabolism*
D001427:Bacterial Toxins; D004791:Enzyme Inhibitors; D052899:Pore Forming Cytotoxic Proteins; D037521:Virulence Factors; C107096:proaerolysin; C032676:aerolysin; D045726:Metalloproteases