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A nuclear-encoded form II RuBisCO in dinoflagellates
D Morse1, P Salois, P Markovic
1Institut de Recherche en Biologie Végétal, Université de Montréal, PQ, Canada.
Science (New York, N.Y.)
|June 16, 1995
Summary
Dinoflagellate chloroplasts possess a unique ribulose-1,5-bisphosphate carboxylase-oxygenase (RuBisCO) form II, typically found in bacteria. This enzyme
Area of Science:
- * Marine biology
- * Molecular evolution
- * Photosynthetic organisms
Background:
- * Dinoflagellate chloroplasts are characterized by three surrounding membranes and the presence of the carotenoid peridinin.
- * The enzyme ribulose-1,5-bisphosphate carboxylase-oxygenase (RuBisCO) is crucial for carbon fixation in photosynthesis.
Purpose of the Study:
- * To investigate the characteristics and genetic origin of RuBisCO in peridinin-containing dinoflagellate chloroplasts.
- * To explore the evolutionary implications of the findings for dinoflagellate chloroplast origins.
Main Methods:
- * Biochemical analysis of RuBisCO in dinoflagellate chloroplasts.
- * Gene sequencing to determine the genetic locus of RuBisCO.
Main Results:
- * Dinoflagellates utilize a form II RuBisCO, a type previously observed only in certain proteobacteria.
- * Unlike other eukaryotes, the gene for this RuBisCO is located in the nuclear DNA, not chloroplast DNA.
Conclusions:
- * The unique form II RuBisCO and its nuclear encoding in dinoflagellates suggest a distinct evolutionary pathway for their chloroplasts.
- * These findings support a non-standard origin for dinoflagellate chloroplasts, potentially involving endosymbiosis with a proteobacterial lineage.