Methanogenic archaea (methanogens) are anaerobic microbes that play critical roles in the cycling of carbon, nitrogen, and sulfur on earth and are also utilized for biotechnological applications, such as biofuel production (e.g. methane). Iron-sulfur (Fe-S) cluster proteins are essential for the ability of methanogens to produce methane and to fix nitrogen using nitrogenase, a complex Fe-S cluster enzyme. The Lessner lab is using genetic and biochemical approaches to elucidate the factors involved in Fe-S cluster biogenesis and in controlling nitrogenase production in methanogens. Research is currently supported by awards from NSF and DOE.