Protein Phycocyanin Structure
This page contains information about accessing structural images of the protein phycocyanin which is the subject of Experiment 1: Protein Folding and Extraction (CHM 1415, General Chemistry II Lab).
The phycocyanin structure file is available from the Research for Collaborative Structural Bioinformatics, RCSB, which is a worldwide repository for processing and distribution of 3-D biological marcomolecular structural data. The RCSB Protein Data Bank is jointly operated by NSF, DOE, and NIH.
You can view the structure directly on the RCSB web site or you can download it to your computer and then view it:
Go to the RCSB homepage. In the search box type 1GH0 which is the id code for phycocyanin. Check the box query by id only and then click find a structure. A summary page of the structure will appear along with a column of links on the left hand side of the page.
Select view structure and a page with several choices for interactive display appears.
A graphics viewer is required to view the structures interactively in a web browser. One option is to download the Chime Plug-in from MDL. This is a free browser plug-in but to get it requires registration with MDL.
If you have Chime select FirstGlance. This will bring up a the structure and a toolbar which allows you to control the struture. NOTE: FirstGlance is recommended since it takes the least amount of time to load.
There are other viewing options besides Chime and these are described on the phycocyanin structure page.
You can download a Chime viewable version directly to your computer by selecting the Download/Display file link. A window will appear giving you a variety of download options. Choose the download option that best matches your system and software. If you are in doubt, select PDB uncompressed under download structure file. If you have UNZIP or GZIP utilities select the appropriate PDB file.
The tetrapyrrole units function as chromophores in this protein. To see them in the structure, make certain ligand is selected. It may also be necessary to deselect water and change the appearance of the structure from ribbons to backbone, etc.
Below is a jpeg image of the protein. The rods represent the protein backbone. The linked five-membered rings in red and blue are the tetrapyrrole units.