• TusA
• Fe-S clusters
• CD
• Thermal Stability
• NMR

TusA is a small sulfurtransferase protein of 81 amino acid residues encoded by yhhP gene in E. Coli. A great number of organisms have similar proteins.
Yamashino et al. showed that a deletion of yhhP gene in E. Coli cells, grown in standard laboratory rich medium (i.e. Luria Broth), leads to physiological general problems which come out with the formation of filamentous cells. TusA also plays a critical role in 2-thio modification of tRNA at the wobble position of U34. It mediates activated-sulfur transfer from desulfurase IscS to the ternary complex TusBCD, allowing sulfur flow towards TusE/MnmA-tRNA complex.
More recently it has been shown that TusA operates within the Moco-dependent pathway. In more details, TusA is not indispensable for Molybdenum cofactor synthesis, but because it and IscU bind to IscS, sulfur is transferred to a particular metabolic pathway by the availability of IscS binding partners. So in the absence of TusA more IscS is available for iron-sulfur cluster biosynthesis. Since [Fe-S] clusters regulate expression for many genes an overproduction of iron sulfur clusters leads to either inactivity for almost all molybdo-enzymes or higher amount of hydrogenase enzyme.
I cloned tusA (yhhP) gene, expressed and characterized the protein through NMR, Mass Spectroscopy and Circular Dichroism. Results from spectra analysis suggest that TusA after expression and purification is a folded protein with a high thermal stability.