Monomeric and bright infrared fluorescent proteins

Patent metadata

Field	Value
Publication number	US-9815870-B2
Application number	US-201414764727-A
Country	US
Kind code	B2
Filing date	Jan 30, 2014
Priority date	Jan 30, 2013
Publication date	Nov 14, 2017
Grant date	Nov 14, 2017

Abstract

The invention described herein features variants related to infrared fluorescent proteins, in particular to mutants of a phytochrome from the bacterium Bradyrhizobium sp. ORS278. The variants show approximately a ten-fold increase in brightness compared to other known infrared fluorescent proteins. The variants are monomeric, allowing them to be used as a protein tag without disrupting the function of the tagged protein of interest.

First claim

We claim:

1. A variant polypeptide of a parent polypeptide,
wherein said variant polypeptide comprises at least 90% identity to SEQ ID NO:2,
wherein the variant polypeptide comprises at least one amino acid substitution at a position selected from the group consisting of position 2, 8, 14, 74, 107, 128, 146, 156, 168, 175, 178, 185, 199, 210, 256, 258, 292, 310, and 320, wherein the numbering of the amino acid positions correspond to that in native BrBphP from Bradyrhizobium sp. ORS278, and
wherein the variant polypeptide is an infrared fluorescent polypeptide.

2. The variant polypeptide of claim 1 , wherein said variant polypeptide comprises at least 95% identity to SEQ ID NO:2.

3. The variant polypeptide of claim 1 , wherein said variant polypeptide comprises SEQ ID NO:2.

4. The variant polypeptide of claim 1 , wherein the variant polypeptide comprises at least one amino acid substitution selected from the group consisting of 2S, 8S, 14F, 74P, 107I, 128I, 146 M, 156I, 168 V, 175N, 178I, 185 A, 199T, 210H, 256M, 258D, 292H, 310T, and 320K.

5. The variant polypeptide of claim 4 , wherein the variant polypeptide comprises the amino acid substitutions 2S, 8S, 14F, 74P, 107I, 128I, 146 M, 156I, 168V, 175N, 178I, 185A, 199T, 210H, 256M, 258D, 292H, 310T, and 320K.

6. The variant polypeptide of claim 1 , wherein the variant polypeptide further comprises amino acid substitution I251C.

7. The variant polypeptide of claim 1 , wherein the polypeptide comprises an amino acid sequence selected from the group consisting of SEQ ID NOS: 10, 12, 14, 16, 18, 20, 22, 24, and 26.

Assignees

• Univ California

Inventors

• Yu Dan
• Shu Xiaokun

Classifications

• G01N33/52

  Use of compounds or compositions for colorimetric, spectrophotometric or fluorometric investigation, e.g. use of reagent paper {and including single- and multilayer analytical elements (immunological elements G01N33/54386; involving labelled immunochemicals G01N33/58; for haemoglobin or occult blood G01N33/72)} · CPC title

• C07K2319/00

  Fusion polypeptide · CPC title

• C07K14/195 Primary

  from bacteria · CPC title

• A61K49/0045

  the fluorescent agent being a peptide or protein used for imaging or diagnosis in vivo · CPC title