HTH - The helix-turn-helix motif is a common prokaryotic...

Info icon This preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
The helix-turn-helix motif is a common prokaryotic DNA-binding element. The HTH motif consists of an ~20 amino acid polypeptide that forms two short helices and a turn. The N-terminal helix is a “bracing” helix. The C-terminal helix is the “recognition helix”. Both make contact with DNA. The recognition helix interacts with the major groove. (Usually, two adjacent helices are contacted by dimeric proteins. Replacement of recognition helix residues may alter binding specificity. “Helix swap” experiments only work in special cases. The recognition helix may project into the major groove at various angles. The proteins with HTH motif usually make additional contacts to DNA. The HTH recognition helix has multiple backbone interactions. The HTH structure and function depend on the rest of the protein. The HTH motifs are evolutionarily related and homologous.
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Organization of the central 20 amino-acid HTH “core” 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 434 repressor Q A Q L A Q K V G T T Q Q S I
Image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern