Solution structure and dynamics of C-terminal regulatory domain of Vibrio vulnificus extracellular metalloprotease

Area of Science:

• Microbiology
• Structural Biology
• Biochemistry

Background:

• Vibrio vulnificus secretes an extracellular metalloprotease (vEP) with prothrombin activation and fibrinolytic activities.
• vEP contributes to bacterial protection by potentially inducing clotting during infection.
• The C-terminal propeptide (C-ter100) of vEP uniquely regulates its activity.

Purpose of the Study:

• To elucidate the structural basis for the regulatory function of vEP's C-terminal propeptide (C-ter100).
• To understand how C-ter100 influences the activity of Vibrio vulnificus extracellular metalloprotease.

Main Methods:

• Multidimensional nuclear magnetic resonance (NMR) spectroscopy was employed to determine the solution structure and backbone dynamics of vEP C-ter100.
• Structural database analysis was performed to compare vEP C-ter100 with known protein structures.
• Fluorescence assays were utilized to investigate the interaction of vEP C-ter100 with iron.

Main Results:

• The solution structure revealed vEP C-ter100 as a rigid, compact β-barrel formation stabilized by hydrophobic and hydrogen bonding networks.
• vEP C-ter100 shares topological similarity with the collagen-binding domain of collagenase, despite low sequence homology.
• Fluorescence assays demonstrated a strong interaction between vEP C-ter100 and iron (Fe(3+)).

Conclusions:

• vEP C-ter100's structure suggests a role in recruiting substrate molecules like collagen.
• The interaction with iron indicates vEP may facilitate iron uptake from host proteins during infection.
• These findings provide insights into the mechanism of Vibrio vulnificus pathogenesis and vEP function.