Chlorophyll is essential for life, directly or indirectly, as the cofactor for the photosynthetic proteins that harvest sunlight and convert it to photochemical energy for the cell. The synthesis of chlorophyll is a globally significant pathway resulting in the formation of the most abundant pigment on Earth. Indeed, with hundreds millions of tonnes synthesised every year chlorophyll biosynthesis and degradation are the only biochemical processes that can be observed from outer space.
Chlorophyl (green) and carotenoids (yellow) molecules bound to the CP47 protein – a subunit of photosystem II. A function of this ‘antenna‘ protein is to direct energy of photon into the reaction center of the photosystem II.
The chlorophyll biosynthesis is quite complicate giving that chlorophyll is synthetized together with other tetrapyrroles such as heme or vitamin B12 in a long branched pathway. Our work is aimed to elucidate how is chlorophyll biosynthesis controlled by the photosynthetic cell, what way is this pigment build into photosynthetic complexes and what is the fate of chlorophyll once these complexes are degraded.
Within the lab we use a broad range of approaches including molecular biology and genetics, protein and pigment biochemistry, enzymology and electron microscopy. Our favoured model organism is the cyanobacterium Synechocystis PCC 6803; an excellent genetic ‘tool’ thanks to its efficiency to integrate DNA into its genome via homologous recombination, which allows a simple inactivation/modification of genes of choice.
The upper part of the picture shows cells of the cyanobacterium Synechocystis PCC 6803 obtained by electron microscopy. Below is the wild type strain together with two genetically modified mutants with changed content of fotosynthetic pigments.