YfdX: Difference between revisions

When a person is infected with typhoid it is spread through the intestinal tract the bloodstream. The reason this disease is so toxic is from <scene name='81/814058/Typhoid_toxin/6'>typhoid toxin</scene>, a unique factor produced by S. typhi (Chong, A., Lee, S., Yang, Y. A., & Song, J. (2017)). The toxin is a different type <scene name='81/814058/Ab_toxin/1'>AB toxin</scene> which means it is made up of one A subunit and 1 B subunit (Chong, A., Lee, S., Yang, Y. A., & Song, J. (2017)). Typhoid toxin has 2 types of A subunits and 1 B subunit. The A subunits are <scene name='81/814058/Ptla/1'>PltA</scene> and <scene name='81/814058/Cdtb/1'>CdtB</scene>, and the B subunit is <scene name='81/814058/Ptlb/1'>PltB</scene> (Chong, A., Lee, S., Yang, Y. A., & Song, J. (2017)). Research has shown that the toxin is made up of 1 molecule of each PltA and CdtB with <scene name='81/814058/5_molecules_of_ptlb/1'>5 molecules of PltB</scene>5 molecules of PltB (Chong, A., Lee, S., Yang, Y. A., & Song, J. (2017)). The combination of Typhoid toxin subunits is what leads it to be very toxic. The typhoid toxin can bind to a wide variety of cells by attaching to certain types of proteins presents on the surface of many cells (Chong, A., Lee, S., Yang, Y. A., & Song, J. (2017)).  These proteins have a specific carbohydrate called glycan and typhoid toxin binds very well to this. Research has shown if there is a reduction in glycans leads to a reduction in typhoid toxin binding (Chong, A., Lee, S., Yang, Y. A., & Song, J. (2017)).  The PltB is thought to be responsible to the binding of the glycans because it has a pocket for the binding of glycans. Typhoid toxin primarily targets immune cells and the central nervous system, leading to the reason why the symptoms are so severe (Chong, A., Lee, S., Yang, Y. A., & Song, J. (2017)).

YfdX weighs around 42kDa and is suggested to be a dimer in solution (Lee, Hye Seon, et al.). It has 10-186 residues from its total 199 amino acids (Lee, Hye Seon, et al.). It is composed of six α-helices, one 310-helix, and three β-strands. These arrange into three subdomains: a four helical bundle, and antiparallel β-sheet, and two helical bundles (Lee, Hye Seon, et al.). The importance of YfdX is that it plays a major role in Salmonella susceptibility to two β-lactam antibiotics, penicillin G and carbenicillin (Lee, Hye Seon, et al.). Without the YfdX protein the Salmonella virulence was enhanced. One specific type of YfdX protein is STY3178. This comes from a multidrug resistant strain of Salmonella Typhi (Saha, P., Manna, C., Das, S., & Ghosh, M. (2016)). The multidrug resistant strains of S. Typhi. have been reported to be resistant to antibiotics such as ciprofloxacin, rifampin, ampicillin, etc. (Saha, P., Manna, C., Das, S., & Ghosh, M. (2016)). The structure of STY3178 was found in a study to be a well folded and predominately α-helical protein containing β-sheets elements (Saha, P., Manna, C., Das, S., & Ghosh, M. (2016)). STY3178 is existing in a trimetric oligomerization state in solution. (Saha, P., Manna, C., Das, S., & Ghosh, M. (2016)). Its ability to bind to antibiotics was found to demonstrate that different small antibiotics are capable of binding to STY3178 such as ciprofloxacin, rifampin, and ampicillin (Saha, P., Manna, C., Das, S., & Ghosh, M. (2016)). Studies show that the binding of ciprofloxacin binding is stronger than rifampin flowed by ampicillin (Saha, P., Manna, C., Das, S., & Ghosh, M. (2016)). This is important to note because if a patient were to come down with typhoid fever and had the STY3178 protein it would be best to see which antibiotic would bind best to the STY3178 protein.