Patent ID: 9238681
Filing Date: 2016-01-19
CPC Classification: C07K,G01N

Claim Text:
1. An isolated polynucleotide comprising a polynucleotide encoding an isolated mutant apoprotein comprising an amino acid sequence wherein the 23rd to 34th amino acids in the amino acid sequence of SEQ ID NO: 2 are substituted with an amino acid represented by formula I below: Xaa23-Xaa24-Xaa25-Xaa26-Xaa27-Xaa28-Xaa29-Xaa30-Xaa31-Xaa32-Xaa33-Xaa34, wherein: Xaa23 is Asp, Glu, Gin, Ser, Thr, or Asn, Xaa24 is Lys, Arg, His, Leu, or Thr, Xaa25 is Asp, Glu, Gin, Ser, Thr, or Asn, Xaa26 is an optional amino acid, Xaa27 is Asp, Glu, Gin, Ser, Thr, or Asn, Xaa28 is Gly, Xaa29 is an optional amino acid, Xaa30 is Ile, Leu, or Val, Xaa31 is Asp, Glu, Gln, Ser, Thr, or Asn, Xaa32 is an optional amino acid, Xaa33 is an optional amino acid, and Xaa34 is Asp, Glu, Gin, Ser, Thr, or Asn; having a function to bind to the peroxide of coelenterazine or the peroxide of a coelenterazine analogue to form a photoprotein capable of emitting light under the action of calcium ions; and having a half decay time of the luminescence emitted by binding of the photoprotein to calcium ions being not less than 2 seconds.