9630186 White At some time during the evolution of the different organisms living on our planet, a fundamental divergence occurred in the biochemistry of the carrier coenzymes responsible for the metabolism of C1 units. There are a group of different C1 carrier coenzymes, known as the modified folates, that have been discovered in the members of the domain Archaea. The current evidence indicates that these modified folates completely replace the typical folates in archaeal metabolism and, as a result, they are able to carry out all of the biochemical reactions normally performed by the folates in the other two domains, the Bacteria, and the Eucarya. This substitution of structurally-modified coenzymes for another coenzyme with the same function is unprecedented, since the structures of coenzymes utilized in biochemical reactions have in general been found to be the same regardless of their origin. This project will attempt to obtain answers as to why this divergence in the structures of the C1 carrier coenzymes has occurred. By studying and comparing the details of the reactions involved in the biosynthesis of folates, and especially the biosynthesis of one of the most studied modified folates in the Archaea, methanopterin, this question may be answered. %%% All of the organisms found on our planet are can be divided into three domains: Archaea, Bacteria, and Eucarya, all of which evolved from a common ancestor, billions of years ago. As the organisms in these different domains evolved, major fundamental biochemical differences in their metabolism arose. The recent discovery of one of these biochemical differences, novel enzyme cofactors in Archae, is the subject of this project. This research that may provide us with a better understanding of the origin of these differences and the early development of life. ***
