Chapter 4- Andy T

Question 1

In nucleotide excision repair what protein initially recognises the DNA damage

Answer 1

XPC-R23

Question 2

What four other proteins join XPC-R23 in nucleotide excision repair

Answer 2

XPA
RPA
TFIIH
XPG

Question 3

What is the role of TFIIH in the nucleotide excision repair

Answer 3

Consists of 6 subunits and contains to DNA helicase activities (XPB and XPD) that unwind the DNA generating a bubble which at the ends comprise junctions (J1 and J2)

Question 4

What is the final heterodimeric subcomplex that binds to the other proteins in nucleotide excision repair makes it a completely assembled NER multiprotein complex

Answer 4

ERCC1-XPF

Question 5

What are the two DNA endonuclease that do the cutting in nucleotide excision repair

Answer 5

XPG

ERCC1-XPF

Question 6

Name a DNA methylating compound

Answer 6

Temozolomide

Question 7

What is bleomycin?

Answer 7

A mixture of cytotoxic glycopeptide antibiotics isolated from a strain of strept verticillus

Question 8

How do bleomycins work

Answer 8

Bind transition metals (Fe Cu) and oxygen and in a one electron reductant can catalyse formation of single stranded and double stranded DNA lesions

Question 9

What in bleomycin is essential to causing double strand DNA cleavage

Answer 9

The linker between the metal and the bithiazole DNA binding domain and the flexibility of the bithiazole moiety itself

Question 10

What are the three common outcomes of bleomycin treatment

Answer 10

Extended cell cycle arrest
Apoptosis
Mitotic cell death

Question 11

Why aren’t bleomycins able to cross cell membranes by free diffusion

Answer 11

They are hydrophilic molecules

Question 12

Which part of bleomycin is thought to play a key role in its cellular uptake

Answer 12

The positively charged tail

Question 13

What 5 things does the bleomycin molecules consist of

Answer 13

Metal binding region 
Bithiazole tail 
Linker region 
Disaccharide 
Positively charged tail