User:Michael Patrick/Sandbox 2: Difference between revisions

=='''GREEN FLUORESCENT PROTEIN'''==

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[[Image:1EMA(GFP).jpg|300px|left|thumb|Green Fluorescent Protein,[[1ema]]]]  [[Image:Aquaria victoria.jpg|300px|right|thumb|''Aquorea victoria'']]

The '''green fluorescent protein''' (GFP) is a protein composed of 238 amino acid residues (26.9kDa) that exhibits bright green fluorescence when exposed to blue light. Although many other marine organisms have similar green fluorescent proteins, GFP traditionally refers to the protein first isolated from the jellyfish ''Aequorea victoria''. The GFP from ''A. victoria'' has a major excitation peak at a wavelength of 395 nm and a minor one at 475 nm. Its emission peak is at 509 nm, which is in the lower green portion of the visible spectrum. The GFP from the sea pansy (''Renilla reniformis'') has a single major excitation peak at 498 nm. In cell and molecular biology, the GFP gene is frequently used as a reporter of expression. In modified forms it has been used to make biosensors, and many animals have been created that express GFP as a proof-of-concept that a gene can be expressed throughout a given organism. The GFP gene can be introduced into organisms and maintained in their genome through breeding, injection with a viral vector, or cell transformation. To date, the GFP gene has been introduced and expressed in many bacteria, yeast and other fungi, fish (such as zebrafish), plant, fly, and mammalian cells, including human. Martin Chalfie, Osamu Shimomura, and Roger Y. Tsien were awarded the 2008 Nobel Prize in Chemistry on 10 October 2008 for their discovery and development of the green fluorescent protein.

Redox sensitive versions of GFP (roGFP) were engineered by introduction of cysteines into the beta barrel structure[14]. The redox state of the cysteines determines the fluorescent properties of roGFP

The nomenclature of modified GFPs is often confusing due to overlapping mapping of several GFP versions onto a single name. For example, mGFP often refers to a GFP with an N-terminal palmitoylation that causes the GFP to bind to cell membranes. However, the same term is also used to refer to monomeric GFP, which is often achieved by the dimer interface breaking A206K mutation.[15] Wild-type GFP has a weak dimerization tendency at concentrations above 5 mg/mL. mGFP also stands for "modified GFP," which has been optimized through amino acid exchange for stable expression in plant cells.