Semester of Graduation

Fall 2019


Master of Science (MS)


Biological Sciences

Document Type



Iron-sulfur (Fe-S) clusters are among the most ancient and prevalent of all biological cofactors. Their assembly into associated proteins is a tightly regulated process with many organisms employing multiple cluster assembly pathways. Much is known about Fe-S cluster assembly in aerobic organisms such as Escherichia coli (E. coli) but little is known in regards to cluster assembly in more ancient organisms such as methanogens. Methanogens are members of the domain of Archaea and are defined by their ability to generate methane as a byproduct of their main energy generating pathway. Methanogens also have significantly higher Fe-S cluster content compared to many aerobic based organisms. In methanogens there is one conserved Fe-S cluster assembly system, the SUF (sulfur mobilization) system. Within the suf operon there are two genes, sufB and sufC, that are conserved across all methanogens. Biochemical analysis revealed that the core SUF system in methanogens is made up of a cluster assembly scaffold with the structure of SufB2C2 and it appears that the Fe-S cluster assembles on the SufC dimer. In vitro analysis revealed that within this complex three conserved cysteine residues within the SufC protein are essential to Fe-S cluster assembly on the scaffold. To evaluate the functionality of the methanogenic SUF system in vivo E. coli was utilized as a host system. It was found that in addition to the three critical cysteine residues on SufC there were two residues on SufB, a cysteine and histidine residue that were also essential to the scaffold’s functionality in vivo.



Committee Chair

Kato, Naohiro