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Structure of interleukin 1 alpha at 2.7-A resolution
B J Graves1, M H Hatada, W A Hendrickson
1Roche Research Center, Hoffmann-La Roche Inc., Nutley, New Jersey 07110.
Biochemistry
|March 20, 1990
Summary
The three-dimensional structure of interleukin-1 alpha (IL-1 alpha) was determined, revealing a capped beta-barrel core with 3-fold symmetry. This structure is similar to interleukin-1 beta (IL-1 beta), providing insights into their shared properties.
Area of Science:
- Structural Biology
- Immunology
- Protein Science
Background:
- Interleukin-1 (IL-1) proteins are key regulators of immune and inflammatory responses.
- IL-1 alpha and IL-1 beta are major isoforms produced by immune cells.
- Understanding their structural similarities and differences is crucial for elucidating their functions.
Purpose of the Study:
- To determine the three-dimensional structure of IL-1 alpha.
- To compare the structural features of IL-1 alpha with IL-1 beta and other related proteins.
- To investigate the internal 3-fold symmetry of IL-1 alpha.
Main Methods:
- Crystallization of IL-1 alpha.
- Structure determination using multiple-wavelength anomalous dispersion (MAD) phasing with selenomethionine incorporation.
- Phasing aided by a single mercury derivative.
- Partial model refinement.
Main Results:
- The 3D structure of IL-1 alpha was solved at 2.7-A resolution.
- The core structure consists of 14 beta-strands and a 3(10) helix, forming a capped beta-barrel.
- The structure exhibits internal 3-fold symmetry, similar to IL-1 beta and soybean trypsin inhibitor.
Conclusions:
- The determined structure of IL-1 alpha provides a detailed molecular basis for its properties.
- The observed structural similarity to IL-1 beta suggests conserved folding patterns within the IL-1 family.
- The 3-fold symmetry is a significant feature of the IL-1 alpha structure.