Question

List and draw the most common motif for prokaryotic DNA binding proteins and be

able to draw how these DNA binding proteins interact with the DNA (remember
there are TWO of these motifs per DNA binding protein!).

Answer 1

The most common motifs for prokaryotic DNA binding proteins are the helix-turn-helix (HTH) and the zinc finger motifs. They allow these proteins to bind to specific DNA sequences, controlling gene transcription by either inducing or silencing it.

Step-by-step explanation:

Common DNA Binding Motifs in Prokaryotic Proteins

The two most common motifs for prokaryotic DNA binding proteins are the helix-turn-helix (HTH) and the zinc finger motif. These motifs facilitate specific interactions between proteins and DNA, allowing proteins to regulate gene expression by binding to particular DNA sequences.

Helix-Turn-Helix (HTH) Motif

The HTH motif is characterized by two α-helices joined by a short sequence of amino acids that makes the 'turn.' One helix fits into the major groove of the DNA and typically contains the DNA recognition sequence, while the other helix supports it.

Zinc Finger Motif

The zinc finger motif consists of a short protein structure stabilized by coordination of one or more zinc ions. This motif also interacts with the major groove of the DNA, and it can be found in various configurations, potentially in clusters, which increases the specificity of DNA binding.

Both motifs are found twice per DNA binding protein, each recognizing specific sequences of DNA, which enables these proteins to control the transcription of genes by either promoting or inhibiting the attachment of RNA polymerase to the DNA.