GTP-binding switch proteins contains two domain-

Switch I- Thr-35

Switch II- Gly-60 

TLS Online TPP Program

#Id: 3281

#Unit 3. Fundamental Processes

MutS has an ATPase activity that is required for mismatch repair, in Escherichia coli, mismatches are detected by a dimer of the mismatch repair protein MutS.

TLS Online TPP Program

#Id: 3282

#Unit 3. Fundamental Processes

In Escherichia coli,  the complex of MutS and the mismatch-containing DNA recruits MutL, a second protein component of the repair system. 

TLS Online TPP Program

#Id: 3283

#Unit 3. Fundamental Processes

In Escherichia coli MMR system, MutL, in turn, activates MutH, an enzyme that causes an incision or nick on one strand near the site of the mismatch.

TLS Online TPP Program

#Id: 3284

#Unit 3. Fundamental Processes

Nicking is followed by the action of a specific helicase (UvrD) and one of three exonucleases.

TLS Online TPP Program

#Id: 3285

#Unit 3. Fundamental Processes

Eukaryotic cells also repair mismatches and do so using homologs to MutS (called MSH proteins for “MutS homologs”) and MutL (called MLH and PMS

TLS Online TPP Program

#Id: 3286

#Unit 3. Fundamental Processes

In BER, A DNA glycosylase recognizes a damaged base (in this case, a uracil) and cleaves between the base and deoxyribose in the backbone.