Protein-Protein Interactions in Photosystem II

Louisiana State University, Baton Rouge LA

Investigators

Abstract

9982395 Bricker Elucidation of the functional properties and structural organization of membrane protein complexes is one of the central objectives of current biochemical investigation. Biological membranes are involved in virtually every aspect of cellular organization and activity. One of the most intriguing aspects of membrane function is its role in the mediation of energy transduction in photosynthetic organisms. Light energy, which is the product of a most violent physical process, fusion, is transformed into biological energy equivalents utilized by the photosynthetic cell. The photosynthetic process provides both the carbohydrate which lies at the base of virtually all food chains and, as a byproduct, all of the atmospheric oxygen utilized by higher organisms. This project investigates the structural interactions between the proteins involved in oxygen evolution. An understanding of the structure of the oxygen-evolving complex will yield new insights into how this important membrane protein complex functions. Protein-protein interactions among the components of the photosystem will be studied using a combination of biochemical and molecular tools. Photosystem II complexes, which are the oxygen-evolving site in photosynthesis will be isolated from both higher plant chloroplasts and blue-green algae (cyanobacteria). These will be studied by a variety of techniques including site-directed mutagenesis, suppressor analysis, chemical modification, fluorescence, and time-resolved oxygen flash yield measurements.