Question

discuss phospholay system that controls bacteria movement.

mus、 Atractants (sugars.amino acids.02) Cell wal Plasma May bind directly or to periplasmic carriers No attractant In the abeence of attractant, CheBP resets the rotor switch by MC No attractant. ChaA kinaseg CheA reset receptor demethylation Aut "off on" t binds MCP, CheA is inactivated, Chel Desensitizes MCP so that higher conc Needed to inactivate CheA Clmb To remain in tumble Che-P must be constantly replenished CheWscoupling protein(activates CheA when no attractant) CheAssensor kinase CheY response regulator (MCPs) Role of in Chemotaxis Demethylation of MCPs when aftractant concentration is constant or concentration Increases, methylation of MCP results in decreases results in a cascade phosphorylation of CheA and CheY.dephosphorylation of CheY by CheZ. Under these conditions, the The CheY interacts with the bacterial flagellum, causing it to rotate Blagellum rotates counterclockwise and the cell makes a straight run clockwise and resulting in a tumble by the cell. When attractant Change in attractant can reverae rotation in 10 sec. In phototaxis light sensors act as MCPs,but same Che system used In Bacillus attractant binding does reverse(Che A and CheY-P stimulate CCW)

Answer 1

Phosphorylation is the addition of a phosphate group to a targeted molecule. By adding a phosphate group, it changes the nature of that molecule and thus it help in triggering a series of cascade reactions, thus resulting in a final reaction. When coming to bacterial locomotion, we are aware that flagella is used for this purpose. The locomotion is attained by the reaction known as chemotaxis which is defined as the movement of a cell or organism by the influence of the gradient of increase/decrease of a chemical substance. Now, what is relation between Phosphorelay by kinases and chemotaxis? the answer is simple, the cascade of reactions triggered by the phosphorylation helps in switching the motor associated the flagella by creating the chemical gradient around it.

To understand the concept better, consider the diagram below.

INNER mEm BRANE Hook