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Amino-acid sequence and three-dimensional structure of the Staphylococcus aureus metalloproteinase at 1.72 A
A Banbula1, J Potempa, J Travis
1Jagiellonian University Institute of Molecular Biology Al. Mickiewicza 3, 31-120, Krakow, Poland.
Background:
Aureolysin is an extracellular zinc-dependent metalloproteinase from the pathogenic bacterium Staphylococcus aureus. This enzyme exhibits in vitro activity against several molecules of biological significance for the host, indicating that it is involved in the pathology of staphylococcal diseases.
Results:
Here we report the amino-acid sequence and inhibitor-free X-ray crystal structure of aureolysin, a member of the thermolysin family of zinc-dependent metalloproteinases. This enzyme, which binds one zinc and three calcium ions, comprises a single chain of 301 amino acids that consists of a beta-strand-rich upper domain and an alpha-helix-rich lower domain.
Conclusions:
The overall structure of aureolysin is very similar to that of the other three members of this family whose structures are known - thermolysin (TLN) from Bacillus thermoproteolyticus, neutral protease (NP) from Bacillus cereus and elastase (PAE) from Pseudomonas aeruginosa. But an important difference has been encountered: in contrast to what has been observed in the other three members of this family (TLN, NP and PAE), inhibitor-free aureolysin displays a 'closed' active site cleft conformation. This new structure therefore raises questions about the universality of the hinge-bending motion model for the neutral metalloproteinases.
Insights
Aureolysin, a Staphylococcus aureus metalloproteinase, has a unique "closed" active site structure. This finding challenges the universal model for neutral metalloproteinase hinge motion.
Area of Science:
- Biochemistry
- Structural Biology
- Microbiology
Background:
- Aureolysin is an extracellular zinc-dependent metalloproteinase from Staphylococcus aureus.
- It plays a role in staphylococcal disease pathology due to its activity against host molecules.
Purpose of the Study:
- To determine the amino acid sequence and X-ray crystal structure of aureolysin.
- To compare the structure of aureolysin with other known metalloproteinases.
Main Methods:
- X-ray crystallography
- Amino acid sequencing
Main Results:
- The inhibitor-free X-ray crystal structure of aureolysin was determined.
- Aureolysin comprises 301 amino acids with distinct beta-strand-rich and alpha-helix-rich domains, binding one zinc and three calcium ions.
- Unlike other family members, aureolysin exhibits a 'closed' active site cleft conformation.
Conclusions:
- The structure of aureolysin is highly similar to thermolysin, neutral protease, and elastase.
- The 'closed' active site conformation of aureolysin raises questions about the hinge-bending motion model in neutral metalloproteinases.
- This discovery offers new insights into metalloproteinase structural dynamics and function.