Spider silk proteins and methods for producing spider silk proteins

An isolated major ampullate spidroin protein, consisting of from 150 to 420 amino acid residues and being defined by the formula REP-CT, wherein

• REP is a protein fragment having from 80 to 300 amino acid residues, wherein said fragment is selected from the group of L(AG)nL, L(AG)nAL, L(GA)nL, L(GA)nGL,
• wherein
• n is an integer from 4 to 8;
• each individual A segment is an amino acid sequence of from 8 to 18 amino acid residues, wherein from 0 to 3 of the amino acid residues are not Ala, and the remaining amino acid residues are Ala;
• each individual G segment is an amino acid sequence of from 12 to 30 amino acid residues, wherein at least 40% of the amino acid residues are Gly;
• and
• each individual L segment is a linker amino acid sequence of from 0 to 20 amino acid residues;
• and
• CT is a protein fragment having from 70 to 120 amino acid residues, which fragment is a C-terminal fragment derived from a major ampullate spidroin protein,
• wherein said CT fragment is, or has at least 80% identity to, an amino acid sequence selected from the group consisting of SEQ ID NO:
• 4, amino acid residues 172-269 of SEQ ID NO:
• 9, and amino acid residues 172-269 of SEQ ID NO:
• 16.