Background
Protein tags have revolutionized many areas of biology, due to their relatively small size, bright fluorescence, the variety of colors and the fact that the tag can be introduced as a single gene or gene fusion. A major limitation of existing fluorescent proteins is the requirement for oxygen in the synthesis of the chromophore, which limits their utility in anaerobes or cells that have been grown in anoxic conditions. Phycobiliproteins are robust, natural proteins found in many cyanobacteria to harvest light that is not efficiently absorbed by chlorophyll for photosynthesis. The complexity of phycobiliprotein biogenesis, in combination with a poor understanding of the enzymes responsible for post-translational modifications, has hindered the widespread adoption of phycobiliproteins as markers and probes.

Invention Description
The inventors have over-expressed certain bilin biosynthesis genes to modify phycobiliprotein production and photochemistry. These various recombinant proteins having each a different color, and corresponding chromophores, have unexpectedly high quantum yield (fluorescence), including under anaerobic conditions. This invention solves the inability of green fluorescent protein (GFP) and its related derivatives to synthesize the chromophore in the absence of molecular oxygen

File Number: 3692 

Other Information:

Status of the Invention

As noted in the accompanying peer-reviewed publications, the invention has been reduced to practice. The invention offers an alternative method of producing in a more efficient, more reproducible manner recombinant phycobiliproteins and their conjugates. The inventors envision a number of potential research tool products, including proteins, chromophores, kits containing them as well as diagnostics. The utility of these highly fluorescent materials within an anaerobic environment may enable the development of completely new applications that previously could not be exploited because of the inherent limitations of oxygen-dependent fluorescent reactions.