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The complete cDNA and polypeptide sequences of human erythroid alpha-spectrin
K E Sahr1, P Laurila, L Kotula
1Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut 06510.
The Journal of Biological Chemistry
|March 15, 1990
Summary
Researchers sequenced human erythroid alpha-spectrin (a protein) using complementary DNA (cDNA) clones. The analysis revealed conserved repeat units within the alpha-spectrin protein structure.
Area of Science:
- Molecular Biology
- Protein Chemistry
- Genetics
Background:
- Spectrin is a critical component of the red blood cell cytoskeleton.
- Understanding spectrin's structure is key to comprehending cellular integrity and function.
Purpose of the Study:
- To determine the complete nucleotide sequence of human erythroid alpha-spectrin.
- To analyze the protein's structural organization, particularly its repeat units.
Main Methods:
- Isolation of overlapping human erythroid alpha-spectrin complementary DNA (cDNA) clones from lambda gt11 libraries.
- Construction of cDNA libraries from human fetal liver and erythroid bone marrow.
- Determination of the composite 8001-base pair (bp) cDNA nucleotide sequence.
Main Results:
- The composite cDNA sequence encodes a polypeptide of 2429 residues.
- Alpha-spectrin is composed of homologous 106-amino acid repeat units, with 17 such repeats identified.
- Specific segments (1-9, 12-19) show high homology, while others exhibit varying degrees of relatedness.
Conclusions:
- The deduced amino acid sequence provides a detailed structural map of human erythroid alpha-spectrin.
- The findings elucidate the repetitive nature of alpha-spectrin, crucial for its function.
- Alpha-spectrin shares evolutionary relationships with other cytoskeletal proteins like alpha-fodrin and alpha-actinin.