Related Experiment Videos
The galactan-binding immunoglobulin Fab J539: an X-ray diffraction study at 2.6-A resolution
1Laboratory of Molecular Biology, National Institute of Diabetes, Digestive and Kidney Diseases, Bethesda, Maryland 20892.
Proteins
|September 1, 1986
Summary
The crystal structure of galactan-binding immunoglobulin J539 Fab was determined at 2.6 A resolution. This mouse antibody reveals a distinct elbow bend and a large antigen-binding cavity, crucial for galactan recognition.
Area of Science:
- Immunology
- Structural Biology
- Biochemistry
Background:
- Immunoglobulin J539 (a mouse IgA, kappa) is known to bind galactans.
- Previous lower-resolution structural data existed for this antibody Fab fragment.
Purpose of the Study:
- To determine the high-resolution crystal structure of the J539 Fab fragment.
- To elucidate the structural basis for galactan binding.
Main Methods:
- X-ray diffraction was used to determine the crystal structure.
- Restrained least-squares refinement was applied to achieve high resolution.
- Model fitting of an oligo-galactan into the antigen-binding site was performed.
Main Results:
- The crystal structure of J539 Fab was determined at approximately 2.6 A resolution.
- The structure exhibits an 'elbow bend' of 145 degrees, differing from other IgA antibodies.
- A large cavity with two clefts, identified as the antigen-binding site, was observed and modeled with galactan.
Conclusions:
- The high-resolution structure provides detailed insights into the J539 antibody's molecular architecture.
- The observed structural features, including the binding cavity, are consistent with its galactan-binding specificity.
- This structural information can inform the design of antibodies with tailored binding properties.