Solution structures of Myb DNA-binding domain and its complex with DNA

Area of Science:

• Structural Biology
• Molecular Biology
• Biochemistry

Background:

• The Myb DNA-binding domain comprises three imperfect tandem repeats.
• Each repeat contains conserved tryptophans and forms a helix-turn-helix-related motif.
• Previous studies determined the solution structure of the third repeat using Nuclear Magnetic Resonance (NMR).

Purpose of the Study:

• To determine the overall structure of the Myb DNA-binding domain.
• To elucidate the DNA-binding mechanism of the Myb DNA-binding domain.
• To investigate the role of each repeat in DNA recognition.

Main Methods:

• Nuclear Magnetic Resonance (NMR) spectroscopy was employed to determine the 3D structure of the entire DNA-binding domain.
• A 16-mer DNA duplex specifically recognized by Myb was synthesized.
• 3D-NMR was used to study the complex between the DNA-binding domain and the DNA duplex.

Main Results:

• The Myb DNA-binding domain exhibits a unique triple helix-turn-helix-related motif.
• Each of the three repeats shares structural similarity, featuring three helices.
• NMR analysis of the Myb DNA-binding domain-DNA complex reveals that the third helix of each repeat likely binds within the major groove of the DNA.

Conclusions:

• The Myb DNA-binding domain possesses a novel structural fold, a triple helix-turn-helix-related motif.
• This unique structure facilitates the binding of Myb to DNA by wrapping around the duplex.
• The Myb DNA-binding domain likely interacts with DNA by positioning its repeated motifs within the major groove.