The glucose uniporter GLUT1 can be purified from the solubilized mixture by antibody affinity chromatography on a column containing either a GLUT1-specific monoclonal antibody or an antibody specific for the epitope tag, then incorporated into liposomes made of pure phospholipids.

TLS Online TPP Program

#Id: 3303

#Unit 3. Fundamental Processes

Nucleotide excision repair in E. coli is largely accomplished by four proteins: UvrA, UvrB, UvrC, and UvrD

TLS Online TPP Program

#Id: 3306

#Unit 3. Fundamental Processes

Unlike base excision repair, the nucleotide excision repair enzymes do not recognize any particular lesion. Rather, this system works by recognizing distortions to the shape of the double helix, such as those

caused by a thymine dimer or by the presence of a bulky chemical adduct on a base.

TLS Online TPP Program

#Id: 3309

#Unit 3. Fundamental Processes

Nucleotide excision repair in human cells. 

A DNA lesion that causes distortion of the double helix, such as a thymine-thymine dimer, is initially recognized by a complex of the XP-C (xeroderma pigmentosum C protein) and 23B proteins.

TLS Online TPP Program

#Id: 3311

#Unit 3. Fundamental Processes

Not only is nucleotide excision repair capable of mending damage throughout the genome, but it is also capable of rescuing RNA polymerase, the progression of which has been arrested by the presence of a lesion in the transcribed (template) strand of a gene, this phenomenon, known as transcription-coupled repair.

TLS Online TPP Program

#Id: 3328

#Unit 3. Fundamental Processes

The significance of transcription-coupled repair is that it focuses repair enzymes on DNA (genes) being actively transcribed.

TLS Online TPP Program

#Id: 3330

#Unit 3. Fundamental Processes

Central to transcription-coupled repair in eukaryotes is the general transcription factor TFIIH.