Which comes first? USU biochemists 'cracking code' of nitrogen fixation

 Utah State University scientists have published two papers in a high profile academic journal this week that unlock mysteries of a chemical process upon which all life on earth depends.

In each paper, the researchers, under the leadership of USU biochemistry professor Lance Seefeldt, describe newly discovered insights about nitrogen fixation, a process that converts life-sustaining nitrogen into a form that humans, animals and plants can access. "It's an incredible irony," says Seefeldt, professor in USU's Department of Chemistry and Biochemistry. "Nitrogen, in the form of dinitrogen, makes up about 80 percent of the air we breathe. We need it to survive and we're swimming in a sea of it, yet we can't get to it."

Humans and animals consume nitrogen in the form of protein from food. Plants obtain nitrogen from the soil. Sounds simple, but it isn't. Nitrogen fixation is a complex and energy-intensive process.

"Dinitrogen consists of two nitrogen atoms joined by one of the strongest triple bonds known in chemistry," says Danyal, a doctoral candidate in Seefeldt's lab. "Breaking these bonds requires tremendous energy, which is released during a cycle of events associated with the transfer of metallic electrons and a chemical reaction called ATP hydrolysis."

USU researchers, as well as others in the science community, have studied steps of this cycle for decades. Yet the nature of the coupling between the electron transfer and ATP hydrolysis and the order in which each occurs has eluded them. Until now.