Comparison of Rubisco Before and After Activation

CPK Color Scheme C O N P

This tutorial will allow you to compare rubisco before and after activation by rubisco activase. View both structures as cartoons, with each subunit a different color and the substrates in CPK as stick figures.

Notice that the activated Rubisco structure (right side) is a homo-tetramer, not an octamer. Also, the activated structure has bound to it an inhibitor rather than a genuine substrate as seen on the inactive rubisco (left side).

Left side: Zoom in to see several copies of the substrate ribulose 1,5-bisphosphate. Does every rubisco subunit binds one ribulose substrate?

Right side: Zoom in to see several copies of a 6-carbon inhibitor (CAP) in CPK colors. Does every rubisco subunit binds one CAP inhibitor?

Left side: Let's get rid of all but one rubisco monomer and look more closely at its structure. The yellow amino acid is lysine #201, the 201^st amino acid in rubisco. Lysine 201 will flash purple and yellow a couple times.

Right side: Let's get rid of all but one rubisco monomer and look more closely at its structure. The yellow amino acid is lysine #201, the 201^st amino acid in rubisco. Lysine 201 will flash purple and yellow a couple times. You should also see the Mg⁺² ion bound to the modified lysine. The modification appears blue.

If you want to start this tutorial over, reset non-activaetd rubisco with a roll by 90 degrees and rotation of 360 degrees.

If you want to start this tutorial over, reset activated rubisco with a roll by 90 degrees and rotation of 360 degrees.

YOu may return to rubisco before activation by itself.

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