Research on Carbon Dioxide Fixation in Photosynthetic Microorganisms (1971–present)

This paper presents my personal account of research on CO2 fixation from when I began these studies as a postdoctoral student in the early 1970s. It traces interests in microbial ribulose bisphosphate carboxylase/oxygenase (Rubisco) and considers early breakthroughs on the isolation, characterization, and significance of this enzyme from nonsulfur purple photosynthetic bacteria and other phototrophic organisms. This article also develops a historical perspective as to how recent efforts may lead to an understanding of molecular mechanisms by which the synthesis of this enzyme and other proteins of the pathway are regulated at the molecular level. In addition, how these studies impinge on the interactive control of CO2 fixation, along with nitrogen fixation and hydrogen metabolism, is also considered. Finally, CO2-fixation studies in green sulfur photosynthetic bacteria and the discovery of the rather surprising Rubisco-like protein are described.