# US 8,772,452 B2 · Calcium-binding photoprotein

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- Number: US 8,772,452 B2
- Document ID: US8772452B2
- Status: Granted
- Kind: B2
- Application number: 12/662,886
- Filed: 2010-05-10
- Published: 2010-12-09
- Granted: 2014-07-08
- Earliest claimed: 2009-05-14
- Assignees: Jnc Corporation
- Applicants: Satoshi Inouye; Yuiko Sahara
- Inventors: Satoshi Inouye; Yuiko Sahara
- Web page: https://patentgrep.com/patent/US8772452B2

## CPC

- C07K 14/43595: {from coelenteratae, e.g. medusae}
- C07K: PEPTIDES (peptides in foodstuffs A23; obtaining protein compositions for foodstuffs, working-up proteins for foodstuffs A23J; preparations for medicinal purposes A61K; peptides containing beta-lactam rings C07D; cyclic dipeptides not having in their molecule any other peptide link than those which form their ring, e.g. piperazine-2,5-diones, C07D; ergot alkaloids of the cyclic peptide type C07D519/02; macromolecular compounds having statistically distributed amino acid units in their molecules, i.e. when the preparation does not provide for a specific; but for a random sequence of the amino acid units, homopolyamides and block copolyamides derived from amino acids C08G69/00; macromolecular products derived from proteins C08H1/00; preparation of glue or gelatine C09H; single cell proteins, enzymes C12N; genetic engineering processes for obtaining peptides C12N15/00; compositions for measuring or testing processes involving enzymes C12Q; investigation or analysis of biological material G01N33/00)

## Abstract

The invention provides calcium-binding photoproteins which can detect light emission with a higher sensitivity. The proteins of the invention comprising the amino acid sequence of SEQ ID NO: 2 can be used for the detection and measurement of calcium ions. The proteins of the invention are useful as reporter proteins, luminescent markers, etc. The polynucleotides of the invention are useful as reporter genes, etc.

## Claims

### Claim 1

A protein as defined by any one of (a) through (d) below:
(a) a protein consisting of the amino acid sequence of SEQ ID NO: 2;
(b) a protein consisting of the amino acid sequence of SEQ ID NO: 2 except that 1 to 3 amino acid(s), excluding amino acids at positions 107, 110, 120, 140, 179 and 180, are substituted with other amino acid(s), wherein the protein can bind to a peroxide of coelenterazine or a peroxide of a coelenterazine derivative to form a holoprotein that emits light in the presence of calcium ions;
(c) a protein comprising the amino acid sequence of SEQ ID NO: 2, which can bind a peroxide of coelenterazine or a peroxide of a coelenterazine derivative to form a holoprotein that emits light in the presence of calcium ions; and,
(d) a protein comprising the amino acid sequence of SEQ ID NO: 2 with 1 to 3 amino acid(s) except for the amino acid(s) at positions 107, 110, 120, 140, 179 and 180 being substituted with other amino acid(s), wherein the protein can bind to a peroxide of coelenterazine or a peroxide of a coelenterazine derivative to form a holoprotein that emits light in the presence of calcium ions.

### Claim 2 (depends on 1)

The protein according to claim 1 which is (a) or (b) below:
(a) a protein consisting of the amino acid sequence of SEQ ID NO: 2; or,
(b) a protein comprising the amino acid sequence of SEQ ID NO: 2, which can bind to a peroxide of coelenterazine or a peroxide of a coelenterazine derivative to form a holoprotein that emits light in the presence of calcium ions.

### Claim 3 (depends on 1)

The protein according to claim 1, further comprising a peptide sequence and/or secretory signal peptide for purification.

### Claim 4 (depends on 1)

A holoprotein comprising the protein according to claim 1 and the peroxide of coelenterazine or the peroxide of a coelenterazine derivative.

### Claim 5 (depends on 1)

A kit comprising the protein according to claim 1 or a holoprotein comprising the protein according to claim 1 and the peroxide of coelenterazine or the peroxide of a coelenterazine derivative.