MOLECULAR MODELING OF RICE RUBISCO

Molecular model of rice Rubisco has been constructed by molecular mode lling method on a computer graphics workstation using graphics softwar e TOM-FRODO and QUANTA/CHARMm, based on the three-dimensional structur e of spinach Rubisco. The molecular modelling was carried out in the f ollowing procedure: amino-acid sequence substitution; manual adjustmen t of the initial model; and energy minimization. The three-dimensional structure of the quaternary complex Rubisco CO2 . Mg2+. CABP of rice Rubisco has also been modelled and optimized using the program package XPLOR. The main-chain structure of rice Rubisco does not show obvious difference from that of spinach Rubisco, and the side-chains are loca ted in the most favorable positions and orientations. The active-site structures are basically the same for the two species. The mutant Leu3 35-->Arg of rice Rubisco has been designed using the graphics software TURBO-FRODO and the program package XPLOR. Energy computation suggest s that this mutation might increase the carboxylation activity.