An Insight of RuBisCO Evolution through a Multilevel Approach

Area of Science:

• Biochemistry and Molecular Biology
• Plant Science
• Evolutionary Biology

Background:

• Ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) is crucial for the global carbon cycle.
• Understanding RuBisCO's structural evolution can enhance crop yields and mitigate CO2 emissions.

Purpose of the Study:

• To investigate how sequence and structural evolution in RuBisCO isoforms (I, II, III) influence flexibility and interactions.
• To identify key residues and structural regions impacting RuBisCO's conformational dynamics and photosynthetic efficiency.

Main Methods:

• Phylogenetic inference
• Multiple sequence alignment
• Normal mode analysis
• Molecular dynamics simulations
• Cross-correlation dynamics analysis

Main Results:

• All three RuBisCO isoforms show increased fluctuations in the loop between alpha-helix B and beta-sheet C.
• A positive correlation was observed between loop 6 flexibility and enzymatic activity, regulating conformational states.
• Specific lysine residues (Lys330 in form II, Lys322 in form III) in loop 6 are vital for enhanced photosynthetic efficiency.
• Cross-correlation analysis revealed altered movement directions of secondary structures across the isoforms.

Conclusions:

• Structural flexibility, particularly in specific loops and residues, is a key evolutionary driver for RuBisCO function.
• Identifying flexible regions and residues provides a basis for enzyme engineering to improve RuBisCO's catalytic efficiency.
• This research offers valuable insights for developing strategies to boost crop productivity and carbon sequestration.