Enhanced CO2/O2 specificity of a site-directed mutant of ribulose-bisphosphate carboxylase/oxygenase. 1992

M R Harpel, and F C Hartman
Protein Engineering Program, Oak Ridge National Laboratory, Tennessee 37831-8077.

The CO2/O2 specificity factor of ribulose-bisphosphate carboxylase/oxygenase partially determines the efficiency of photosynthetic carbon assimilation. Heretofore, engineered alterations of the enzyme have only decreased the selectivity for CO2 utilization. We show that alanyl replacement of active-site Ser-368 of the Rhodospirillum rubrum carboxylase enhances the carboxylation selectivity approximately 1.6-fold over the wild-type level. This enhancement reflects a greater relative decline in oxygenase efficiency than in carboxylase efficiency. In contrast to wild-type enzyme, the carboxylase activity of the Ser-368 mutant protein is not perceptibly inhibited by O2, perhaps indicative of a change in rate-limiting steps in the overall reaction pathway.

UI MeSH Term Description Entries
D010100 Oxygen An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration. Dioxygen,Oxygen-16,Oxygen 16
D002245 Carbon Dioxide A colorless, odorless gas that can be formed by the body and is necessary for the respiration cycle of plants and animals. Carbonic Anhydride,Anhydride, Carbonic,Dioxide, Carbon
D012247 Rhodospirillum rubrum Vibrio- to spiral-shaped phototrophic bacteria found in stagnant water and mud exposed to light.
D012273 Ribulose-Bisphosphate Carboxylase A carboxy-lyase that plays a key role in photosynthetic carbon assimilation in the CALVIN-BENSON CYCLE by catalyzing the formation of 3-phosphoglycerate from ribulose 1,5-biphosphate and CARBON DIOXIDE. It can also utilize OXYGEN as a substrate to catalyze the synthesis of 2-phosphoglycolate and 3-phosphoglycerate in a process referred to as photorespiration. Carboxydismutase,Ribulose Biphosphate Carboxylase-Oxygenase,Ribulose Diphosphate Carboxylase,Ribulosebiphosphate Carboxylase,Rubisco,1,5-Biphosphate Carboxylase-Oxygenase,Ribulose Biphosphate Carboxylase,Ribulose Bisphosphate Carboxylase,Ribulose-1,5-Biphosphate Carboxylase,Ribulose-1,5-Biphosphate Carboxylase-Oxygenase,Ribulose-1,5-Bisphosphate Carboxylase Small-Subunit,Ribulose-Bisphosphate Carboxylase Large Subunit,Ribulose-Bisphosphate Carboxylase Small Subunit,Rubisco Small Subunit,1,5 Biphosphate Carboxylase Oxygenase,Biphosphate Carboxylase-Oxygenase, Ribulose,Carboxylase Small-Subunit, Ribulose-1,5-Bisphosphate,Carboxylase, Ribulose Bisphosphate,Carboxylase, Ribulose Diphosphate,Carboxylase, Ribulose-1,5-Biphosphate,Carboxylase, Ribulose-Bisphosphate,Carboxylase, Ribulosebiphosphate,Carboxylase-Oxygenase, 1,5-Biphosphate,Carboxylase-Oxygenase, Ribulose Biphosphate,Carboxylase-Oxygenase, Ribulose-1,5-Biphosphate,Diphosphate Carboxylase, Ribulose,Ribulose 1,5 Biphosphate Carboxylase,Ribulose 1,5 Biphosphate Carboxylase Oxygenase,Ribulose 1,5 Bisphosphate Carboxylase Small Subunit,Ribulose Biphosphate Carboxylase Oxygenase,Ribulose Bisphosphate Carboxylase Large Subunit,Ribulose Bisphosphate Carboxylase Small Subunit,Small Subunit, Rubisco,Small-Subunit, Ribulose-1,5-Bisphosphate Carboxylase
D013379 Substrate Specificity A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts. Specificities, Substrate,Specificity, Substrate,Substrate Specificities
D015870 Gene Expression The phenotypic manifestation of a gene or genes by the processes of GENETIC TRANSCRIPTION and GENETIC TRANSLATION. Expression, Gene,Expressions, Gene,Gene Expressions
D016297 Mutagenesis, Site-Directed Genetically engineered MUTAGENESIS at a specific site in the DNA molecule that introduces a base substitution, or an insertion or deletion. Mutagenesis, Oligonucleotide-Directed,Mutagenesis, Site-Specific,Oligonucleotide-Directed Mutagenesis,Site-Directed Mutagenesis,Site-Specific Mutagenesis,Mutageneses, Oligonucleotide-Directed,Mutageneses, Site-Directed,Mutageneses, Site-Specific,Mutagenesis, Oligonucleotide Directed,Mutagenesis, Site Directed,Mutagenesis, Site Specific,Oligonucleotide Directed Mutagenesis,Oligonucleotide-Directed Mutageneses,Site Directed Mutagenesis,Site Specific Mutagenesis,Site-Directed Mutageneses,Site-Specific Mutageneses

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