Patent ID: 8748132

Claim:
A nucleic acid fragment consisting of a nucleotide sequence coding for a protein that forms an inclusion body when expressed in prokaryotic cells (inclusion body-forming protein), said fragment comprising a nucleotide sequence coding for a signal peptide and a nucleotide sequence coding for a protein of interest, wherein the signal peptide consists of the sequence of SEQ ID NO: 1 with: (i) a substitution of leucine at the 13th position with any one of the amino acids selected from the group consisting of proline, phenylalanine and tryptophan, or (ii) a substitution of leucine at the 13th position as set forth in (i) and a substitution of alanine at the 21st position with any one of the amino acids selected from the group consisting of aspartic acid, glutamic acid, lysine, histidine, phenylalanine and tyrosine.