Molecular Mechanisms of Transcription Activation and Repression

Question 1

How do zinc-finger motifs interact with DNA?

Answer 1

They interact with DNA’s MAJOR GROOVE in a SEQUENCE SPECIFIC MANNER.

Question 2

What are the 2 types of zinc-finger motifs?

Answer 2

C2H2 zinc finger (most common DNA binding motif in humans)

C4 zinc fingers: (in about 50 human transcrip-on factors of the nuclear receptor family)

Question 3

How does the C2H2 zinc finger interact with DNA?

Answer 3

Binding of ions is done by two cysteine and two histidine residues, which compacts the domain and allows insertion of the α-helix into the major groove of the DNA.

1 molecule

Question 4

How does the C4 zinc finger interact with DNA?

Answer 4

These proteins generally contain only two such units but bind as homodimers. These have two-fold rotational symmetry and bind to consensus DNA sequences that are inverted repeats.

2 molecules