DNA Binding Proteins

Question 1

Where on the DNA molecule do proteins frequently bind to and what are they known as?

Answer 1

Homodimers bind to the major groove of DNA

Question 2

What are the THREE structures of DNA binding proteins?

Answer 2

1. Helix-turn-helix motif
2. Zinc-finger domain
3. Leucine zipper domain

Question 3

What THREE things may happen when a DNA-binding protein connects with its recognition sequence?

Answer 3

1. Catalyse specific reaction on DNA (DNA Methylation)
2. Block transcription (Negative regulation - LacI)
3. Activate transcription (Positive regulation - cAMP-CAP)

Question 4

What will a binding of a protein to DNA fragment cause in Agarose Gel Electrophoresis?

Answer 4

Changes its mobility (make it move slower through the gel)