Related Experiment Videos
Purification, composition, and structure of macrophage adhesion molecule.
1Center for Blood Research, Boston, Massachusetts 02115.
Biochemistry
|January 12, 1988
Summary
This study characterizes Macrophage Adhesion Molecule (MAM), a heterodimer found on guinea pig neutrophils. Researchers purified MAM and analyzed its subunits, MAM-alpha and MAM-beta, revealing distinct structural and compositional features crucial for its function.
Area of Science:
- Immunology
- Molecular Biology
- Protein Chemistry
Background:
- Macrophage Adhesion Molecule (MAM) is a neutrophil surface heterodimer.
- It is the guinea pig homolog of Mo1 and Mac-1.
Purpose of the Study:
- To purify and characterize the MAM heterodimer and its subunits.
- To investigate the structural and compositional properties of MAM-alpha and MAM-beta.
Main Methods:
- Purification of MAM from peritoneal neutrophils using lentil lectin and M2-antibody chromatography.
- Dissociation of the heterodimer and separation of subunits via acidic conditions and M7-antibody chromatography.
- Analysis of protein composition, amino acid content (especially cysteine), carbohydrate content, and antibody reactivity.
Main Results:
- MAM-beta is a cysteine-rich polypeptide requiring disulfide bonds for structural integrity.
- MAM-alpha is a larger polypeptide with a higher mannose content compared to MAM-beta.
- Both subunits are glycoproteins with N-linked carbohydrate units.
Conclusions:
- MAM is a complex heterodimer with distinct alpha and beta subunits.
- The structural features of MAM-beta, particularly disulfide bonds, are critical for its conformation.
- Detailed characterization provides insights into MAM's role in cellular adhesion.