Evolution of photosynthesis
We have produced some of the most detailed and disruptive studies on the evolution of photosynthesis in the history of the subject. And more is yet to come!
We combine molecular evolution methods with structural and functional data of the enzymatic complexes to understand when and how life’s energy systems originated and diversified.
Evolution of Type II reaction centre proteins. For more information visit Cardona et al. 2019, Geobiology.
Ancestral sequence reconstruction
We have now taken the evolution of photosynthesis a step further. We are using a combination of molecular evolution methods, synthetic biology, and site-directed mutagenesis to reconstruct ancestral stages in the history of the photosystems oxygenic photosynthesis.
Adaptive evolution
We are tracing and mapping genetic and molecular changes of model cyanobacteria through selection for survival when grown under conditions of interest.
The aim of these experiments is to observe in real time the photosystems and their light harvesting complexes adapting to novel functions. We have observed, through our extensive work modelling the dynamics of the rates of evolution that when cyanobacteria conquered niches with atypical light conditions, a substantial acceleration of the rates of evolution occurred (see the figure above, panel A). This suggest a strong adaptability potential limited only by natural selection.
Directed evolution
We are developing and implementing directed evolution methods to radically alter the chemistry of both Photosystem I and II. To do this we exploit a natural evolved ability of the photosystems that allow these heavy-duty enzymes to be tremendously plastic: its function can be tuned and changed by swapping the core subunits.
We are exploring several interesting pathways, for example: can Photosystem II be evolved to oxidise water using a different configuration of the manganese cluster? Or, can Photosystem II be evolved to oxidise something else other than water? Can we evolve new photosystems by chimerising photosystem I with reductive enzymes to drive their chemistry entirely by light?
