RuBisCO: Difference between revisions

This scene shows an <scene name='46/463261/8ruc_active-site/1'>isolated α-β barrel</scene> (cartoon and colored for secondary structure) of spinach Rubisco [[8ruc]], bound to the naturally occurring inhibitor 2-carboxylarabinitol-1,5-bisphosphate (CAP) and Mg²⁺, both shown in CPK spacefill. [[Image:CAP.jpg|left|]]The structure of CAP (left figure) is similar to the hydrated reaction intermediate that is formed following the addition of CO₂ to RUBP. This <scene name='46/463261/8ruc_active-site/5'> overview of the active site</scene> shows that CAP sits at one end of the α-β barrel, and only residues from the beta strands (gold ball & stick) and loops that link them to helices (silver ball & stick) contribute binding RUBP and Mg²⁺ (the residue contributed by the N-terminal lobe of the adjacent subunit is not shown). The <scene name='46/463261/8ruc_active-site/6'>types of residues</scene> involved are <font color='red'>acidic</font> residues that interact with Mg²⁺, <font color='blue'>basic</font> residues and <font color='lightblue'>histidines</font> that interact with phosphate and hydroxyl groups, <font color='orchid'>polar</font> residues that interact with hydroxyl groups, one <font color='slategray'>hydrophobic</font> residue, and backbone atoms (white).