Interaction of Chloroplast and Nuclear Genomes in Regulating RuBP Carboxylase Activity

Expression strategies for the synthesis of higher-plant and cyanobacterial RuBP carboxylase genes in Escherichia coli have been developed to facilitate the study of the assembly pathway and properties of the enzyme’s large (L) and small (S) subunit proteins. The genes for the L and S subunits of the RuBP carboxylase of wheat and of a cyanobacterium, Synechococcus 6301 have been cloned into bacteriophage and plasmid vectors such that they are transcribed and translated in E. coli. To date no RuBP carboxylase activity has been detected in extracts prepared from E. coli cells synthesizing the wheat L and S subunits, although both gene products were present and soluble. Sucrose gradient analysis of cell extracts from E. coli synthesizing both L and S demonstrated that the soluble wheat L polypeptide was present as a large protein aggregate that contained no S subunits. With the cloned cyanobacterial genes, RuBP carboxylase activity could be recovered in E. coli cell extracts when the L and S gene products were synthesized from genes present on the same, or separate, replicons. Solubility and sedimentation studies of the cyanobacterial L subunits synthesized in the absence of S showed that the L subunit was soluble and present in E. coli as an L 8 structure. The E. coli extracts containing only the L subunit exhibited no detectable RuBP carboxylase activity. Infection of the E. coli cells containing L subunits with an M13 phage expressing the cyanobacterial S gene led to the assembly of functional RuBP carboxylase in these cells. This demonstrates the essential role of the S subunit in allowing the formation of an active enzyme.

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Regulation of RuBP carboxylase activity associated with photo-inhibition of wheat

Photosynthesis Research ◽

10.1007/bf00040708 ◽

1982 ◽

Vol 3 (2) ◽

pp. 105-111 ◽

Cited By ~ 11

Author(s):

F. A. Bovle ◽

A. J. Keys

Keyword(s):

Rubp Carboxylase ◽

Carboxylase Activity

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Effects of artificial frost hardening and winter stress on net photosynthesis, photosynthetic electron transport and RuBP carboxylase activity in seedlings of Pinus silvestris

Physiologia Plantarum ◽

10.1111/j.1399-3054.1980.tb03299.x ◽

1980 ◽

Vol 48 (4) ◽

pp. 526-531 ◽

Cited By ~ 42

Author(s):

GUNNAR OQUIST ◽

LAILA BRUNES ◽

JAN-ERIK HALLGREN ◽

KERSTIN GEZELIUS ◽

MONICA HALLEN ◽

...

Keyword(s):

Electron Transport ◽

Net Photosynthesis ◽

Photosynthetic Electron Transport ◽

Pinus Silvestris ◽

Rubp Carboxylase ◽

Carboxylase Activity ◽

Frost Hardening

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Immunocytochemical studies on the behavior of RuBisCO and LHCP II during the cell cycle of synchronized Euglena gracilis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100160868 ◽

1990 ◽

Vol 48 (3) ◽

pp. 662-663

Author(s):

Tetsuaki Osafune ◽

Shuji Sumida ◽

Tomoko Ehara ◽

Eiji Hase ◽

Jerome A. Schiff

Keyword(s):

Cell Cycle ◽

Immunoelectron Microscopy ◽

Growth Phase ◽

Euglena Gracilis ◽

Dark Period ◽

Light Period ◽

Carboxylase Activity ◽

Immunocytochemical Studies ◽

Lhcp Ii

Changes in the morphology of pyrenoid and the distribution of RuBisCO in the chloroplast of Euglena gracilis were followed by immunoelectron microscopy during the cell cycle in a light (14 h)- dark (10 h) synchronized culture under photoautotrophic conditions. The imrnunoreactive proteins wereconcentrated in the pyrenoid, and less densely distributed in the stroma during the light period (growth phase, Fig. 1-2), but the pyrenoid disappeared during the dark period (division phase), and RuBisCO was dispersed throughout the stroma. Toward the end of the division phase, the pyrenoid began to form in the center of the stroma, and RuBisCO is again concentrated in that pyrenoid region. From a comparison of photosynthetic CO2-fixation with the total carboxylase activity of RuBisCO extracted from Euglena cells in the growth phase, it is suggested that the carboxylase in the pyrenoid functions in CO2-fixation in photosynthesis.

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