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: An object of the present invention is to provide a method for producing an artificial structural protein fiber having a small diameter and having a stress equal to or higher than that of the related art. A method for producing an artificial structural protein fiber according to the present invention is a method for producing an artificial structural protein fiber by a wet spinning method, the method including a coagulation step of discharging a spinning dope containing an artificial structural protein and an organic solvent from a spinneret into a coagulation liquid to coagulate the artificial structural protein, wherein a bath draft in the coagulation step is more than 0.4 and 20 or less.

Abstract: An object of the present invention is to provide a method for producing a modified fibroin multifilament excellent in productivity and a multifilament produced by the same. The multifilament of the present invention contains modified fibroin, in which the multifilament has 100 or more constituent single yarns, a coefficient of variation in elastic modulus is 15% or less, a coefficient of variation in strength is 15% or less, and a coefficient of variation in elongation is less than 33%.

Abstract: Disclosed is a method for producing a protein fiber, the method including: bringing a spinning dope containing a protein and an organic solvent into contact with a coagulation liquid to coagulate the protein, wherein a content of the protein in the spinning dope is more than 10% by mass based on a total amount of the spinning dope, and the coagulation liquid contains water or an aqueous solution of pH 0.25 or more and pH 10.00 or less.

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 recovering protein, which recovers a target protein from a mixture containing the target protein and a material different from the target protein, the method including a dissolution step of dissolving either the target protein or the material by applying pressure while heating to a solution for dissolution containing the mixture and a polar solvent, and a separation step of separating an obtained solution.

Abstract: The present invention relates to a modified fibroin including a domain sequence represented by Formula 1: [(A)n motif-REP]m, in which the domain sequence has an amino acid sequence locally containing a region with locally high hydropathy index equivalent to an amino acid sequence in which one or a plurality of amino acid residues in REP are substituted with amino acid residues with a high hydropathy index and/or one or a plurality of amino acid residues with a high hydropathy index are inserted into REP, as compared to naturally occurring fibroin. In Formula 1, (A)n motif represents an amino acid sequence consisting of 4 to 20 amino acid residues and the number of alanine residues relative to the total number of amino acid residues in the (A)n motif is 83% 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 and the like may be the same amino acid sequence or different amino acid sequences.

Abstract: The present invention provides a method for producing a molded article including a step 1 of adding water to a composition including a structural protein, a step 2 of molding a water-containing composition obtained in the step 1, and a step 3 of drying the molded composition obtained in the step 2 to obtain the molded article.

Abstract: Provided is a method for producing a protein solution, including applying a pressure to a dispersion liquid containing a protein and a polar solvent in which the protein is dispersed, to obtain a protein solution containing the protein and the polar solvent in which the protein is dissolved.