Mapping the domain structure of human erythrocyte adducin.
Adducin is a 200-kDa heterodimeric protein associated with the erythrocyte membrane skeleton which binds to Ca2+/calmodulin, promotes binding of spectrin to actin, and is a substrate for protein kinases C and A. Adducin polypeptides can be structurally and functionally divided into two distinct regions. The amino-terminal 39-kDa domain of each subunit is more basic and resistant to proteases than the C-terminal 60-64-kDa domain, which is very sensitive to proteolytic degradation. Two-dimensional peptide map analysis revealed that the 39-kDa protease-resistant domains represent a portion of adducin which is highly conserved between the alpha and beta subunits whereas the protease-sensitive regions are different in each subunit. Comparison of the structural and functional properties of purified 39-kDa domains with intact adducin showed that the 39-kDa domains were not phosphorylated by protein kinases C or A and did not bind to Ca2+/calmodulin or interact with spectrin and actin. This suggests that the protease-sensitive domains may perform the various functions of adducin since these activities were all lacking from the protease-resistant domains. It is also possible that the conserved and variable domains are both required for one or more activities of adducin or that the 39-kDa domains play a role in maintaining the oligomeric state of adducin necessary for interaction of the variable domains with spectrin-actin complexes.
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Related Subject Headings
- Trypsin
- Protein Conformation
- Peptide Mapping
- Peptide Fragments
- Molecular Weight
- Macromolecular Substances
- Humans
- Erythrocytes
- Electrophoresis, Polyacrylamide Gel
- Electrophoresis, Gel, Two-Dimensional
Citation
Published In
ISSN
Publication Date
Volume
Issue
Start / End Page
Location
Related Subject Headings
- Trypsin
- Protein Conformation
- Peptide Mapping
- Peptide Fragments
- Molecular Weight
- Macromolecular Substances
- Humans
- Erythrocytes
- Electrophoresis, Polyacrylamide Gel
- Electrophoresis, Gel, Two-Dimensional