Question

predict whether an E. coli cell with a deletion of the following genes can grow on glucose as a sole carbon source. Explain why or why not.

Hint #1: Think about what the cells need to synthesize in order to survive.

Hint #2: keep an eye out for isozymes – enzymes that catalyze the same reaction but are encoded by different genes

hisB

aroF

fumA

nadB

edd

Answer 1

Before answering the question you need to know about the functions of all the genes. These are-

The hisB gene, found in E. coli encodes a protein involved in catalysis of two-step in histidine biosynthesis (the sixth and eight step), namely the bifunctional Imidazole glycerol-phosphate dehydratase/histidinol-phosphatase.

Aro F gene forms a protein that performs Stereospecific condensation of phosphoenolpyruvate and D-erythrose-4-phosphate giving rise to 3-deoxy-D-arabino-heptulosonate-7-phosphate (DAHP). It is involved in step 1 of the subpathway that synthesizes chorismate from D-erythrose 4-phosphate and phosphoenolpyruvate.

fumA gene forms a protein that Catalyzes the reversible hydration of fumarate to (S)-malate. It Functions as an aerobic enzyme in the direction of malate formation as part of the citric acid cycle. Accounts for about 80% of the fumarase activity when the bacteria grow aerobically.

nadB gene forms a protein that Catalyzes the oxidation of L-aspartate to iminoaspartate.

edd gene forms a protein that Catalyzes the dehydration of 6-phospho-D-gluconate to 2-dehydro-3-deoxy-6-phospho-D-gluconate. This protein is involved in the pathway Entner-Doudoroff pathway, which is part of Carbohydrate metabolism.

Now after looking at the functions of above-mentioned genes, it can be ascertained that the genes fum A and edd are responsible for carbohydrate metabolism hence if these are removed E.coli would not be able to grow on glucose as it will not be able to metabolize the glucose in that case.