Algae and certain types of bacteria use CO2 for photosynthesis and are prime sources for biomass for bio-fuel production. By genetically altering proteins which participate in photosynthesis, these species can efficiently conduct this process in both normal and extreme temperatures.
The present invention addresses the shortcomings of the presently known plants and microalgea by providing the means to generate novel, genetically modified photosynthetic organisms that maintain photosynthetic activity and growth under a wide temperature range (15-45oC). The invented technology has already been applied and demonstrated on cyanobacteria that generate free hydrogen under selected conditions with presently available techniques and is expected to be applicable to microalgea and higher plants in the future. It involves replacement of 1-2 amino acid residues in a protein motif within the D1 protein subunit of photosystem II (PSII). PSII is the protein complex responsible for the conversion of solar energy to a useful form of energy that drives oxygen generation and carbohydrates formation by plants in the process of photosynthesis. The revealed motif enables adaptation of the photosynthetic machinery to the ambient temperature of photosynthetic bacteria, microalgea and higher plants. We found that specific residues in this motif can modulate the physiological temperature of these organisms (kerner-Shlik et al, Nature, 2006) as well as its carbon dioxide fixation ability. Thus changes in these residues provided thermostability and plasticity to the modified organisms at a much broader range than observed for the native organisms.