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AssigneeNat'l Institute of Advanced Industrial Science and Technology
InventorsShinya Honda, Hideki Watanabe, Masayuki Tsukamoto
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A modified protein of an extracellular domain of protein A, which has the reduced ability to bind to immunoglobulin in an acidic region, compared with the wild-type extracellular domain of protein A, without impairing a selective antibody-binding activity in a neutral region. On the basis of three-dimensional structure coordinate data on a complex of the extracellular domain of protein A bound with the Fc region of immunoglobulin G, the modified protein is obtained by the substitution of amino acid residues that are located within the range of 10 angstroms from the Fc region and have a 20% or more ratio of exposed surface area, by histidine residues. Preferably, the modified protein is obtained by the substitution of amino acid residues at sites identified from the analysis of sequences selected from a library constituted by the protein group, by histidine residues. These substitutions may be combined.
A mutant protein derived from the B domain protein of protein A of the amino acid sequence set forth in SEQ ID NO:
A mutant protein derived from the Z domain protein of protein A of the amino acid sequence set forth in SEQ ID NO:
A mutant protein derived from the E domain protein of protein A of the amino acid sequence set forth in SEQ ID NO:
A mutant protein derived from the D domain protein of protein A of the amino acid sequence set forth in SEQ ID NO:
A mutant protein derived from the A domain protein of protein A of the amino acid sequence set forth in SEQ ID NO:
A mutant protein derived from the C domain protein of protein A of the amino acid sequence set forth in SEQ ID NO:
Dependencies are inferred from the claim text.