Wednesday, March 2, 2011

Rubisco Images

RuBisCo, or ribulose-1,5-bisphosphate carboxylase oxygenase has 16 chains - 8 large chains and 8 small chains. Each large chain is paired with a small chain, forming a heterodimer. The heterodimers further dimerize, forming four-chain complexes which are axial symmetrical. Four identical tetramers circle up to form the overall protein. Above, the protein is color coded by chain. The long chains are green or blue and the short chains are yellow or red. Each quadrant (blue or green) has two large chains. The small chains fit above (toward the viewer) or below (away from the viewer, on the back side) the large chains, and they are slightly offset, sitting in between the large chain subunits.
To further explore the structure, the image above shows just one of the tetrameric subunits: two large chains and two small chains. In this image, the large chains are the darker shade and the small chains are the lighter shade. One large-small chain dimer is red, while the other is blue. This view is from the side of the protein, and the viewer is on the outside of the protein looking in. The spheres are ribulose-1,5-bisphosphate, the substrate of the protein.
Breaking down the structure further, a large-small chain dimer is shown above. This view is from the side of the large chain which normally faces the other long chain in the tetrameric subunit. The beta barrel with corresponding alpha helices surrounding it is visible under the substrate. The right-most portion of the structure contains a beta sheet. These structural features are portrayed more clearly in the image of the long chain below.
Because this protein is so large and complex, it does not lend itself well to more complicated images, for example, stick or line images displaying every amino acid, or mesh images displaying the contours of the surface, both of which are pictured below. These views mimic the first image in this post. The viewer is above the protein, looking down through the center of it.


  1. That title alone is a winner. What's going on in that last pic? Is that a chicken wire representation?