Answer:
e. PhoU keeps PhoR bound to the phosphate transporter protein Pst
Explanation:
PhoU is a membrane protein known to regulate the transport of phosphate (Pi) between cellular compartments. It has been discovered that mutations in this protein cause lethality because the cell becomes incapable of controlling the intracellular levels of Pi, this being toxic for the cell. PhoR is a histidine kinase/phosphatase. When the Pi level is considered to be a limiting factor, PhoR autophosphorylates at a histidine residue and then donates its phosphoryl group to PhoB. On the other hand, when the Pi level is high, this protein removes the phosphoryl group from phospho-PhoB. Finally, the Pst is a signal transduction protein that acts as a transporter capable of switching its conformation during the transport of PI.
In molecular biology, restriction fragment length polymorphism, orRFLP, is a technique that exploits variations in homologous DNA sequences. It refers to a differencebetween samples of homologous DNAmolecules from differing locations ofrestriction enzyme sites, and to a related laboratory technique by which these segments can be illustrated. InRFLP analysis, the DNA sample is broken into pieces and (digested) byrestriction enzymes and the resultingrestriction fragments are separated according to their lengths by gel electrophoresis. Although now largely obsolete due to the rise of inexpensive DNA sequencing technologies, RFLP analysis was the first DNA profilingtechnique inexpensive enough to see widespread application. RFLP analysis was an important tool in genome mapping, localization of genes forgenetic disorders, determination of riskfor disease, and paternity testing.
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