Low Activation State of Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase in Carboxysome-Defective Synechococcus Mutants

摘要: The high-CO2-requiring mutant of Synechococcus sp. PCC 7942, EK6, was obtained after extension the C terminus small subunit ribulose-1,5-bisphosphate (RuBP) carboxylase/oxygenase (Rubisco). carboxysomes in EK6 were much larger than wild type, but cellular distribution large and sub-units Rubisco not affected. kinetic parameters vitro-activated similar type. On other hand, appeared to be a low state activation situ cells pretreated with an air level CO2. This deduced from appearance lag phase when carboxylation followed time permeabilized by detergent subsequently supplied saturating CO2 RuBP. Pretreatment high virtually abolished lag. After low-CO2 treatment, internal RuBP pool higher wild-type cells; pretreatment reduced cells. We suggest that phenotype mutants possess aberrant arises inactivated are exposed