Question

In dam methylation mismatch repair, which protein translocates to the GATC site and is able to bind to two sites simultaneously, thus making a DNA loop?

A. MutL

B. MutS

C. MutH

D. UvrD

Answer 1

In dam methylation mismatch repair in E. coli, MutS is the protein that binds to two sites simultaneously at the GATC site, making a DNA loop which is crucial for the repair mechanism.

Step-by-step explanation:

In the dam methylation mismatch repair system of E. coli, the protein that translocates to the GATC site and is capable of binding to two sites simultaneously to create a DNA loop is MutS. Initially, MutS binds to the mismatched DNA and recruits MutL.

Subsequently, MutL activates MutH, which cleaves the newly synthesized daughter strand at the GATC site. This cleavage is essential for the removal of the mismatched base and the eventual repair of the DNA strand.

Answer 2

In dam methylation mismatch repair, the protein that binds to the GATC site and creates a DNA loop is MutL, which works in conjunction with MutS and MutH to recognize and repair mismatches in DNA replication.

Step-by-step explanation:

In the process of dam methylation mismatch repair, the protein that translocates to the GATC site and is capable of binding to two sites simultaneously, creating a DNA loop, is MutL.

his protein, along with MutS and MutH, plays a critical role in recognizing and repairing mismatches that occur during DNA replication. MutS initially recognizes and binds to the mismatch. Then, MutL binds to MutS and the two recruits MutH to the DNA. MutL is involved in the formation of a loop in the DNA to facilitate the repair process. MutH specifically cleaves the newly synthesized daughter strand that is not methylated, thereby distinguishing it from the parental strand.

Following the incision made by MutH, exonuclease enzymes remove the section of the DNA containing the mismatch. DNA polymerase III then fills in the gap with the correct nucleotide, and the strand is finally sealed by DNA ligase. This intricate mechanism ensures the fidelity of the genetic information being passed on during cell division and is essential for maintaining the stability of an organism's genome.