Method for detecting target substance, and tag, DNA, vector, probe and detection kit for use therewith

A tag comprising:

• a polypeptide forming an α-helix structure, the α-helix structure of the tag comprising seven or more consecutive amino acid residues of an amino acid sequence represented by the following structural formula (1):
• {X1-X2-X3-X4-X5-X6-X7}N (1)
• wherein N is an integer of 2 or greater;
• X3 and X6 are each an acidic amino acid or a basic amino acid;
• X2 and X6 are each a hydrophobic amino acid;
• and X1, X4 and X7 are each any amino acid,
• wherein the tag is designed for being bound to a target substance, and is used in a method for detecting the target substance comprising:
• bringing into contact with each other (a) the tag bound to the target substance, and (b) a probe comprising a compound bound to a fluorescent dye;
• and
• measuring the fluorescence emitted by the fluorescent dye,
• wherein a binding of the α-helix structure of the tag to the compound of the probe induces a spectral change in the fluorescence emitted by the fluorescent dye.

DNA encoding a tag, the tag comprising:

• a polypeptide forming an α-helix structure, the α-helix structure of the tag comprising seven or more consecutive amino acid residues of an amino acid sequence represented by the following structural formula (1):
• {X1-X2-X3-X4-X5-X6-X7}N (1)
• wherein N is an integer of 2 or greater;
• X3 and X5 are each an acidic amino acid or a basic amino acid;
• X2 and X6 are each a hydrophobic amino acid;
• and X1, X4 and X7 are each any amino acid,
• wherein the tag is designed for being bound to a target substance, and is used in a method comprising:
• bringing into contact with each other (a) the tag bound to the target substance, and (b) a probe comprising a compound bound to a fluorescent dye;
• and
• measuring the fluorescence emitted by the fluorescent dye,
• wherein a binding of the α-helix structure of the tag to the compound of the probe induces a spectral change in the fluorescence emitted by the fluorescent dye.

A vector having DNA inserted therein, wherein the DNA encodes a tag, the tag comprising:

• a polypeptide forming an α-helix structure, the α-helix structure of the tag comprising seven or more consecutive amino acid residues of an amino acid sequence represented by the following structural formula (1):
• {X1-X2-X3-X4-X5-X6-X7}N (1)
• wherein N is an integer of 2 or greater;
• X3 and X5 are each an acidic amino acid or a basic amino acid;
• X2 and X6 are each a hydrophobic amino acid;
• and X1, X4 and X7 are each any amino acid,
• wherein the tag is designed for being bound to a target substance, and is used in a method comprising:
• bringing into contact with each other (a) the tag bound to the target substance, and (b) a probe comprising a compound bound to a fluorescent dye;
• and
• measuring the fluorescence emitted by the fluorescent dye,
• wherein a binding of the α-helix structure of the tag to the compound of the probe induces a spectral change in the fluorescence emitted by the fluorescent dye.

A probe comprising:

• a polypeptide forming an α-helix structure, the α-helix structure of the probe comprising seven or more consecutive amino acid residues of an amino acid sequence represented by the following structural formula (1):
• {X1-X2-X3-X4-X5-X6-X7}N (1)
• wherein N is an integer of 2 or greater;
• X3 and X5 are each an acidic amino acid or a basic amino acid;
• X2 and X6 are each a hydrophobic amino acid;
• and X1, X4 and X7 are each any amino acid,
• and at least one of amino acid residues X2 and X6 present in at least one α-helix structure of the probe is substituted with a molecule bound to a fluorescent dye,
• wherein the probe is used in a method for detecting a target substance, comprising:
• bringing into contact with each other (a) a tag comprising a polypeptide forming an α-helix structure, the tag bound to the target substance, and (b) the probe;
• and
• measuring the fluorescence emitted by the fluorescent dye,
• wherein a binding of the α-helix structure of the tag to the polypeptide of the probe induces a spectral change in the fluorescence emitted by the fluorescent dye.

A detection kit for a target substance, comprising at least one of a tag, DNA encoding the tag and a vector having the DNA inserted therein, along with a probe,

• wherein
• the tag comprises a polypeptide forming an α-helix structure, the α-helix structure of the tag comprising seven or more consecutive amino acid residues of an amino acid sequence represented by the following structural formula (1):
• {X1-X2-X3-X4-X5-X6-X7}N (1)
• wherein N is an integer of 2 or greater;
• X3 and X5 are each an acidic amino acid or a basic amino acid;
• X2 and X6 are each a hydrophobic amino acid;
• and X1, X4 and X7 are each any amino acid,
• the probe comprises a polypeptide forming an α-helix structure, the α-helix structure of the probe comprising seven or more consecutive amino acid residues of an amino acid sequence represented by the following structural formula (1):
• {X1-X2-X3-X4-X5-X6-X7}N (1)
• wherein N is an integer of 2 or greater;
• X3 and X5 are each an acidic amino acid or a basic amino acid;
• X2 and X6 are each a hydrophobic amino acid;
• and X1, X4 and X7 are each any amino acid,
• and at least one of amino acid residues X2 and X6 present in at least one α-helix structure of the probe is substituted with a molecule bound to a fluorescent dye, and
• the tag is designed for being bound to the target substance, and the tag, the DNA, the vector, and the probe is used in a method for detecting the target substance comprising:
• bringing into contact with each other (a) the tag, and (b) the probe;
• and
• measuring the fluorescence emitted by the fluorescent dye,
• wherein a binding of the α-helix structure of the tag to the polypeptide of the probe induces a spectral change in the fluorescence emitted by the fluorescent dye.