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Membrane-SPINE: A Biochemical Tool to Identify Protein-protein Interactions of Membrane Proteins In Vivo
Published on: November 7, 2013
Structure of the integral membrane protein CAAX protease Ste24p
Edward E Pryor1, Peter S Horanyi, Kathleen M Clark
1Membrane Protein Structural Biology Consortium, USA.
Science (New York, N.Y.)
|March 30, 2013
Summary
Researchers determined the crystal structure of Ste24p, a protease crucial for protein maturation. This reveals the enzyme
Area of Science:
- Biochemistry
- Structural Biology
- Molecular Biology
Background:
- Posttranslational lipidation, specifically isoprenylation, modifies protein function.
- Isoprenoids attach to proteins with C-terminal CAAX motifs, followed by proteolytic cleavage.
Purpose of the Study:
- To determine the crystal structure of the CAAX protease Ste24p.
- To elucidate the mechanism of proteolytic cleavage in yeast mating pheromone a-factor maturation.
Main Methods:
- X-ray crystallography to determine the three-dimensional structure of Ste24p.
- Analysis of the Ste24p core structure, including transmembrane helices and active site cavity.
Main Results:
- The crystal structure of Ste24p, a zinc metalloprotease, was determined.
- Ste24p features a ring of seven transmembrane helices enclosing a large cavity with the active site.
- The cavity is accessible via gaps between the helices, suggesting a mechanism for substrate processing.
Conclusions:
- The Ste24p structure provides insights into the mechanism of CAAX protease activity.
- A processive mechanism involving substrate insertion, translocation, and ejection is hypothesized for cleavage.
- Understanding Ste24p function is critical for protein maturation pathways.
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