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Updated: Jul 4, 2026
08:26
Measuring the 50% Haemolytic Complement (CH50) Activity of Serum
Published on: March 29, 2010
Structure of and influence of a tick complement inhibitor on human complement component 5
Folmer Fredslund1, Nick S Laursen, Pietro Roversi
1Department of Molecular Biology, University of Aarhus, DK-8000 Aarhus, Denmark.
Nature Immunology
|June 10, 2008
Summary
Researchers determined the crystal structure of human complement component 5 (C5), revealing its core resembles C3. This structural insight aids in designing novel complement inhibitors.
Area of Science:
- Structural Biology
- Immunology
- Biochemistry
Background:
- The complement system is crucial for innate immunity.
- Human complement component 5 (C5) plays a pivotal role in the terminal pathway of complement activation.
- Understanding C5 structure is key to developing targeted therapeutics.
Purpose of the Study:
- To elucidate the three-dimensional structure of human C5.
- To provide insights into the functional and structural properties of C5.
- To lay the groundwork for structure-based drug design.
Main Methods:
- X-ray crystallography was employed to determine the crystal structure of C5.
- The structure was resolved at a resolution of 3.1 Å.
- The interaction between C5 and the tick inhibitor OmCI was investigated.
Main Results:
- The core structure of C5 closely resembles that of complement component 3 (C3).
- The C345C domain is flexibly attached to the C5 core, unlike in C3.
- Binding of OmCI stabilized C5 conformation but did not obstruct the convertase cleavage site.
Conclusions:
- The determined C5 structure provides a detailed molecular understanding of this complement protein.
- The findings facilitate the development of novel, selective complement inhibitors.
- This structural information is valuable for therapeutic strategies targeting the complement cascade.
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