Rubisco specificity factor tends to be larger in plant species from drier habitats and in species with persistent leaves

Abstract

The specificity factor of Rubisco is a measure of the relative capacities of the enzyme to catalyse carboxylation and oxygenation of ribulose 1,5-bisphosphate and hence to control the relative rates of photosynthetic carbon assimilation and photorespiration. Specificity factors of purified Rubisco from 24 species of C 3 plants found in diverse habitats with a wide range of environmental growth limitations by both water availability and temperature in the Balearic Islands were measured at 25 ∞ ∞ ∞ ∞C. The results suggest that specificity factors are more dependent on environmental pressure than on phylogenetic factors. Irrespective of phylogenetic relationships, higher specificity factors were found in species characteristically growing in dryer environments and in species that are hemideciduous or evergreen. Effects of temperature on specificity factor of the purified enzyme from 14 species were consistent with the concept that higher specificity factors were associated with an increase in the activation energy for oxygenation compared to carboxylation of the 2,3-enediolate of RuBP to the respective transition state intermediates. The results are discussed in terms of selection pressures leading to the differences in specificity factors and the value of the observations for identifying useful genetic manipulation to change Rubisco polypeptide subunits.

Adaptive signals in algal Rubisco reveal a history of ancient atmospheric carbon dioxide

“…(c) Carbon dioxide as a driver for Rubisco adaptation There is evidence that Rubisco adaptation in land plants was driven by a number of environmental factors in addition to atmospheric composition, including aridity and high temperatures [50]. However, in the marine realm, we propose that it is the change in atmospheric CO 2 equilibrated with surface waters which acts as the ultimate driver of positive selection in Rubisco.…”

Screening of HighkcatRubisco among Poaceae for Improvement of Photosynthetic CO2Assimilation in Rice

“…These parameters can vary with plant species and affect the Rubisco specificity factor. In fact, Galmes et al (2005) ). Bunsen absorption coefficients were used to convert Kc and Ko values from concentration to partial pressure.…”

The Catalytic Properties of Hybrid Rubisco Comprising Tobacco Small and Sunflower Large Subunits Mirror the Kinetically Equivalent Source Rubiscos and Can Support Tobacco Growth

“…Only needing to engineer rbcL would be advantageous as it would negate the need for cotransplanting in the complementary RbcS and evade further obstacles with needing to silence the endogenous S or genetically manipulate it as this is complicated by the multiple RbcS copies in the nuclear genome . Candidate rbcL genes for testing would include those of the kinetically superior Rubiscos from C 3 plants growing in hot arid conditions (Galmes et al, 2005), such as Limonium gibertii (Parry et al, 2007) whose L shows 92% identity to tobacco L. A wider examination might also include rbcL genes from C 4 Rubiscos that characteristically have higher k c cat values relative to C 3 species, albeit at the expense of higher K c values (Yeoh et al, 1981;Seemann et al, 1984).…”