Abstract: The present invention relates to a modified fibroin including a domain sequence represented by Formula 1: [(A)nmotif-REP]m or Formula 2: [(A)nmotif-REP]m?(A)n motif, in which the domain sequence has an amino acid sequence with a reduced content of a glutamine residue equivalent to an amino acid in which one or a plurality of glutamine residues in REP are deleted or substituted with other amino acid residues, as compared with a naturally occurring fibroin.

Abstract: The present invention relates to a method for manufacturing a protein fiber, including an extension and contraction step of contracting or extending a protein raw fiber containing a protein by bringing the protein raw fiber into contact with a liquid or vapor; and a drying step of drying the protein raw fiber that has undergone the extension and contraction step while adjusting a length of the protein raw fiber to an arbitrary length.

Abstract: The present invention relates to a modified fibroin including a domain sequence represented by Formula 1: [(A)n motif-REP]m or Formula 2: [(A)n motif-REP]m-(A)n motif, in which the domain sequence has an amino acid sequence with a reduced content of a glutamine residue equivalent to an amino acid in which one or a plurality of glutamine residues in REP are deleted or substituted with other amino acid residues, as compared with a naturally occurring fibroin. [In Formula 1 and Formula 2, (A)n motif represents an amino acid sequence consisting of 4 to 27 amino acid residues, and the number of alanine residues with respect to the total number of amino acid residues in the (A)n motif is 80% or more. REP represents an amino acid sequence consisting of 10 to 200 amino acid residues. m represents an integer of 10 to 300. A plurality of (A)n motifs may be the same amino acid sequence or different amino acid sequences.

Abstract: The present invention relates to a method for manufacturing a protein fiber, including an extension and contraction step of contracting or extending a protein raw fiber containing a protein by bringing the protein raw fiber into contact with a liquid or vapor; and a drying step of drying the protein raw fiber that has undergone the extension and contraction step while adjusting a length of the protein raw fiber to an arbitrary length.