The Amino Acid Sequence of the Tryptophan-Containing Subunit (α-Subunit) of Bovine Brain S-100 Protein |
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Authors: | Toshiaki Isobe Tsuneo Okuyama |
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Affiliation: | Department of Chemistry, Faculty of Science, Tokyo Metropolitan University, Tokyo, Japan |
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Abstract: | Abstract: The tryptophan-containing subunit (α-subunit) of bovine brain S-100 protein was purified from a S -aminoethyl derivative of S-100a protein, and its amino acid sequence was determined. The α-subunit contained 93 residues, including one tryptophan, and had a molecular weight of 10,400. The sequence shows an extensive homology (58% identity) to the sequence of another "tryptophan-free" subunit (β-subunit) found in both S-100a and S-100b protein, and has a calcium binding site characteristic of the "E-F hand" proteins, such as calmodulin or troponin C. The tryptophan residue is located at position 90 which is presumably adjacent to the C-terminal end of the α-helix following the calcium binding loop, and thus appears likely to serve as a specific probe in structure-function studies of S-100a protein. |
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Keywords: | S-100 protein Subunits Amino acid sequence |
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