University of Maryland, College Park
Election Year: 1996
Primary Section: 25, Plant Biology
Secondary Section: 62, Plant, Soil, and Microbial Sciences
Membership Type: Member
As a plant biologist, I have studied the structure of the photosynthetic apparatus in plant cells fundamental for converting solar energy into chemical energy on virtually all life is dependent. By isolating novel pigment protein complexes (phycobilisomes), we demonstrated that they consisted of three principal bilin-type pigments that absorb light energy in the visible region where chlorophyll absorption is minimal. In cyanobacteria, the progenitors of chloroplasts, we found that the molecular architecture of phycobilisomes was highly similar to those in red algae. The contribution of phycobilisomes in extending the light absorption capacity for photosynthesis was shown by the functional attachment of phycobilisomes with photosystem II reaction centers by the evolution of oxygen when the bilin-type pigments were selectively excited by light. We are now investigating the assembly and functional development of carotenoid-chlorophyll complexes of photosynthetic membranes. Also, we are studying the in vitro and in situ functional insertion of carotenoids and chlorophyll into apoproteins of light-harvesting complexes. Such studies are important in defining the role of carotenoids in energy absorption and photoprotection and in elucidating the evolutionary progression of photosynthetic organisms.