Many neurological and metabolic disorders have been traced to the malfunction of electron transport system proteins. The flavodoxins are a low molecular weight flavoenzyme which has been shown to be a fine model for larger dehydrogenases. B-phycoerythrin is a photon transferring protein which is being used as a model for electron transferring proteins (a relatively small step quantum mechanically) which also possess the opportunity to examine protein subunit interactions. The primary purpose of this project is to provide amino acid sequences for assistance in completing x-ray diffraction studies which are in progress. The value of providing another flavodoxin sequence comes from being able to examine homology, protein interactions, and catalytic site distances for a complete electron transfer system for the same organism. The value of examining the B-phycoerythrin sequence comes from being able to provide the first complete biliprotein structure in three dimensions. In both cases, important information will become available for comparative evolution studies, mechanism of genetic duplications and information on the convergence or divergence of electron and photon transferring protein structures. The overall objective is to gain insight into cofactor-apoenzyme interactions, subunit interactions and transfer mechanisms as they relate to catalytic reaction rate enhancement.