Part:BBa_K4689613

Ribulose bisphosphate carboxylase small chain (rbcS)

rbcS is a protein subunit that forms part of the complete RuBisCO enzyme complex. RuBisCO, or ribulose-1,5-bisphosphate carboxylase/oxygenase, is a pivotal enzyme in photosynthesis found in the chloroplasts of plant cells and the chloroplast-like organelles of other photosynthetic organisms. RBCS is responsible for encoding the small subunits of RuBisCO.

Significance in the Calvin Cycle:

rbcS plays a crucial role in the Calvin cycle, which is the biochemical process responsible for carbon fixation in photosynthetic organisms:

1. Carbon Fixation: In the initial step of the Calvin cycle, RuBisCO catalyzes the carboxylation of ribulose-1,5-bisphosphate (RuBP) by combining it with carbon dioxide (CO2) from the atmosphere. This reaction results in the formation of two molecules of 3-phosphoglycerate (3-PGA).

2. Role in RuBisCO Formation: While RBCS itself is not directly involved in the carboxylation reaction, it encodes the small subunits that combine with the large subunits of RuBisCO to form the complete enzyme complex.This full RuBisCO enzyme is essential for the efficient carboxylation of RuBP and subsequent carbon fixation.

3. Conversion of 3-PGA: The 3-PGA molecules generated by RuBisCO, with the assistance of RBCS, serve as the starting point for the synthesis of sugars and other organic compounds in the Calvin cycle. Through a series of enzymatic reactions, these compounds are further processed and transformed, providing energy and carbon skeletons for the plant's growth and metabolism. Regeneration of RuBP: The small subunits encoded by RBCS contribute to the structural integrity of RuBisCO, which plays a crucial role in the regeneration of RuBP. RuBP is essential for the continual operation of the Calvin cycle, as it is used in subsequent rounds of carboxylation by RuBisCO.

Usage and Biology

Sequence and Features

Assembly Compatibility:

• 10
  COMPATIBLE WITH RFC[10]
• 12
  COMPATIBLE WITH RFC[12]
• 21
  COMPATIBLE WITH RFC[21]
• 23
  COMPATIBLE WITH RFC[23]
• 25
  COMPATIBLE WITH RFC[25]
• 1000
  COMPATIBLE WITH RFC[1000]

References:

1.Patel, M., & Berry, J. O. (2008). Rubisco gene expression in C4 plants. Journal of Experimental Botany, 59(7), 1625-1634.

2.Pottier, M., Gilis, D., & Boutry, M. (2018). The hidden face of Rubisco. Trends in Plant Science, 23(5), 382-392.