Horseshoe crab factor B variant
AssigneeSeikagaku Corporation
InventorsYuki Kobayashi, Hikaru Mizumura, Toshio Oda, Shun-ichiro Kawabata
Life of this patent
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Abstract
Provided is a technology related to a horseshoe crab factor B variant, and also provided is means for performing endotoxin measurement with high sensitivity. A polypeptide having an amino acid sequence in which the amino acid residue at the 193-position in an amino acid sequence of a polypeptide of horseshoe crab factor B is substituted with a cysteine (Cys) residue, is produced. Endotoxin measurement can be carried out with high sensitivity by combining this polypeptide with horseshoe crab factor C, as a Limulus reagent.
Claims8
A polypeptide represented by any one of the following (A) to (C):
- (A) a polypeptide having an amino acid sequence represented by the following (A1) or (A2):
- (A1) an amino acid sequence represented by amino acid numbers 1 to 400 of SEQ ID NO:
- 7;
- and
- (A2) an amino acid sequence represented by amino acid numbers 24 to 400 of SEQ ID NO:
- 7,
- (B) a polypeptide having an amino acid sequence including substitution, deletion, insertion, and/or addition of one amino acid residue or a plurality of amino acid residues in the amino acid sequence of the polypeptide represented by the item (A), provided that the cysteine (Cys) residue at the 193-position is neither substituted nor deleted, and having an identity of at least 90% to at least one of the amino acid sequences of the polypeptides represented by item (A), and the polypeptide having the function of horseshoe crab factor B, and
- (C) a polypeptide having an amino acid sequence of a fusion polypeptide in which a peptide tag is added to the polypeptide represented by any one of the items (A) to (B), the polypeptide having the function of horseshoe crab factor B,
- wherein the function of horseshoe crab factor B is to be activated in contact with an activated horseshoe crab factor C, and cleaving a horseshoe crab proclotting enzyme.
A DNA having any one of the following (a) and (b):
- (a) a DNA having a base sequence according to any one of the following (a1) to (a4):
- (a1) a base sequence consisting of base numbers 1 to 1200 of SEQ ID NO:
- 5;
- (a2) a base sequence consisting of base numbers 70 to 1200 of SEQ ID NO:
- 5;
- (a3) a base sequence consisting of base numbers 1 to 1200 of SEQ ID NO:
- 6;
- and
- (a4) a base sequence consisting of base numbers 70 to 1200 of SEQ ID NO:
- 6, and
- (b) a DNA having the base sequence of a fusion DNA in which a peptide tag-encoding DNA is added to the DNA according to any one of the items in (a), the DNA encoding a polypeptide having the function of horseshoe crab factor B.
Dependencies are inferred from the claim text.