Homework 3

The Question :

　 The green fluorescent protein (GFP) from the jellyfish Aequorea victoria is rapidly becoming an important reporter molecule for monitoring gene expression and protein localization in vivo, in situ and in real time. GFP emits bright green light (lambda max = 509 nm) when excited with UV or blue light (l max = 395 nm, minor peak at 470 nm). The fluorescence excitation and emission spectra of GFP are similar to those of fluorescein, and the conditions used to visualize this fluorophore are also suitable for GFP. Unlike other bioluminescent reporters, the chromophore in GFP is intrinsic to the primary structure of the protein, and GFP fluorescence does not require a substrate or cofactor. GFP fluorescence is stable, species-independent and can be monitored non-invasively in living cells and, in the case of transparent organisms, whole animals.

1. How many references can you find about green fluorescent protein (GFP) within five years ?
2. How many papers were done by P. Kitts ?
3. How many of these references are related to structure ?
4. Can you find a paper describe its crystal structure ? Give its abstract on your homepage.

The answer

1. We use the PubMed to search references about green fluorescent protein within 5 yeras. We find 613 references about green fluorescent protein.

2. We go on using  above limits and add another limit (author name- P. Kitts), we find there are 6 documents.  

3. We use limits-GFP, structure and 5 years to serach references. We find 76 documents fitting the limits.

4. We find the the paper about crystal structure of GFP. The abstract of paper is bleow :

Science 1996 Sep 6;273(5280):1392-1395

Crystal structure of the Aequorea victoria green fluorescent
protein.

Ormo M, Cubitt AB, Kallio K, Gross LA, Tsien RY, Remington SJ

Institute of Molecular Biology and Department of Physics, University of Oregon, Eugene, OR
97403-1226, USA.

The green fluorescent protein (GFP) from the Pacific Northwest jellyfish Aequorea victoria has
generated intense interest as a marker for gene expression and localization of gene products. The
chromophore, resulting from the spontaneous cyclization and oxidation of the sequence -Ser65
(or Thr65)-Tyr66-Gly67-, requires the native protein fold for both formation and fluorescence
emission. The structure of Thr65 GFP has been determined at 1.9 angstrom resolution. The
protein fold consists of an 11-stranded beta barrel with a coaxial helix, with the chromophore
forming from the central helix. Directed mutagenesis of one residue adjacent to the
chromophore, Thr203, to Tyr or His results in significantly red-shifted excitation and emission
maxima.