Organization and Expression of Genes for Photosynthetic Pigments–Protein Complexes in Photosynthetic Bacteria

Publisher Summary This chapter provides an overview of the organization and expression of the genes for the photosynthetic apparatus in photosynthetic prokaryotes as revealed in combined studies utilizing genetics, biochemistry, and molecular biology. Photosynthesis, the conversion by living organisms of light into chemical energy, is a fundamental biological process on earth. Purple non-sulfur bacteria normally inhabit muddy lake bottoms and sewage lagoons. They have a remarkable ability to adapt metabolically in response to changes in oxygen tension, light intensity, and available nutrients in their environment. Such changes are likely to occur in the mud of ponds and ditches; in the littoral zones of lakes, rivers, and seas; and in all kinds of sewage lagoons. The multiple modes of growth seem to parallel the evolution of the earth's atmosphere from an initial reducing environment of hydrogen, ammonia, and methane through the synthesis of organic acids and depletion of ferrous iron in the oceans, to the development of an oxidizing environment through the action of the cyanobacteria.