Expression and partial characterization of an elastase from Chromobacterium violaceum.

Area of Science:

• Veterinary Pathology
• Microbiology
• Biochemistry

Background:

• Chromobacterium violaceum infection in a Chinese red panda resulted in severe necrotizing lesions in multiple organs, particularly the lungs.
• Bacterial aggregates within lung lesions suggested a potential role for bacterial virulence factors.

Purpose of the Study:

• To investigate if Chromobacterium violaceum produces an elastase enzyme.
• To characterize the elastolytic activity and its potential contribution to observed pathology.

Main Methods:

• Elastolytic activity was assessed using elastin Congo red and elastin nutrient agar assays with C. violaceum strains.
• Enzyme activity was localized to the periplasmic fraction and characterized regarding growth phase, pH optimum, and inhibitor sensitivity.
• Enzyme purification and molecular weight estimation were performed using polyacrylamide gel electrophoresis.

Main Results:

• Both C. violaceum strains exhibited significant elastolytic activity.
• The enzyme activity was regulated by growth phase and elastin availability, peaking in late logarithmic phase.
• The elastase was identified as a zinc metalloproteinase, optimal at neutral pH, and sensitive to EDTA and 1,10-phenanthroline.
• Purified elastase activity corresponded to a band of approximately 30kDa.

Conclusions:

• Chromobacterium violaceum produces a zinc metalloproteinase with elastolytic activity.
• This elastase is likely a virulence factor contributing to the necrotizing lung lesions observed in the red panda.
• Further research into C. violaceum virulence factors is warranted.