Crystallization and preliminary X-ray diffraction studies of an a1/alpha 2/DNA ternary complex

Area of Science:

• Molecular Biology
• Structural Biology
• Biochemistry

Background:

• The yeast a1/alpha 2 homeodomain heterodimer is a transcription factor that regulates gene expression.
• Understanding the structural basis of protein-DNA recognition is crucial for deciphering gene regulation mechanisms.

Purpose of the Study:

• To obtain high-resolution crystals of the yeast a1/alpha 2 homeodomain heterodimer bound to a specific DNA site.
• To elucidate the three-dimensional structure of this ternary complex.

Main Methods:

• Crystallization of the protein-DNA complex using cobaltic hexamine.
• X-ray diffraction analysis of flash-frozen crystals at -179 degrees C.
• Determination of crystal space group and unit cell dimensions.

Main Results:

• Crystals of the ternary complex were obtained in space group P6(1) or P6(5).
• Diffraction data were collected to 2.7 A along the c-axis and 2.4 A in perpendicular directions.
• The crystal structure revealed one protein-DNA complex per crystallographic asymmetric unit.

Conclusions:

• The successful crystallization and diffraction analysis provide a foundation for determining the atomic structure of the yeast a1/alpha 2 homeodomain-DNA complex.
• This structural information will enhance our understanding of specific DNA binding by homeodomain proteins.