In the lab, you isolate a mutant strain of bacteria in which the phosphatase that would normally dephosphorylate NtrC-P is defective. Assuming the levels of NtrB and NtrC protein remain normal (same as wild type), what is the expected phenotype of this mutant

GlnA will be overexpressed and the cells will have more glutamine than glutamate

Explanation:

Glutamine synthetase (glnA) is an enzyme involved in nitrogen metabolism that catalyzes the amidation of glutamate to glutamine. Moreover, the phosphorylated form of the NtrC response regulator protein (NtrC~P) acts as a transcriptional activator of genes associated with nitrogen metabolism, including glnA. NtrC~P exhibits 1-an enhanced DNA binding activity (increased oligomerization on the target DNA template) and 2-ATPase activity (oligomerization of the NtrC phosphoprotein), which are fundamental features for transcriptional activation. In consequence, it is expected that a higher level of NtrC~P (due to a defective form of the phosphatase that dephosphorylates NtrC~P) leads to the overexpression of glnA, thereby increasing glutamine levels and simultaneously decreasing glutamate concentration.

a

explanation: