What did scientists discover?
For DNA to reproduce, its double helix must be made to unwind so that new double helices can be synthesized from each of the two strands. Helicase is the protein "machine" that pulls the two strands apart. Researchers have used the MagLab's 14.5 tesla mass spectrometer to map the contact surfaces when helicase and DNA form a complex, in order to reveal the unwinding mechanism used by the helicase.
Scientists knew that double-stranded DNA is held inside the helicase protein structure. They thought unwound single strands were unconstrained outside the protein. This research revealed that the single strands are in fact tightly held to the helicase protein surface, helping the helicase pull the DNA helix apart from both ends. The information sheds an important light on the fundamental process of cell division.
THE TOOLS THEY USED
This research was conducted in the On-Line Liquid Chromatography Electrospray Ionization 14.5 T FT-ICR Mass Spectrometer at the MagLab's ICR Facility.
Why is this important?
With this information, scientists could map the sites of the DNA binding to the helicase protein during the DNA unwinding process. The information sheds an important light on the fundamental process of cell division.
Who did the research?
Brian W. Graham1, Yeqing Tao4, Katie L. Dodge3, Carly T. Thaxton3, Danae Olaso3, Nicolas L. Young4,5, Alan G. Marshall2,4, and Michael A. Trakselis3
1U. Pittsburgh; 2Florida State U.; 3Baylor U.; 4MagLab; 5Baylor College of Medicine
Why did they need the MagLab?
This research required a technique (hydrogen–deuterium exchange) available at the MagLab that breaks the protein into dozens of pieces. Each piece was then identified using ultra-high-resolution ion cyclotron mass spectrometry. With this information, scientists could map the sites of the DNA binding to the helicase protein during the DNA unwinding process.
Details for scientists
- View or download the expert-level Science Highlight, Binding Sites for DNA on a DNA-Unwinding Protein, Probed by Hydrogen/ Deuterium Exchange and Ion Cyclotron Resonance Mass Spectrometry
- Read the full-length publication, DNA Interactions Probed by Hydrogen Deuterium Exchange (HDX) Fourier Transform Ion Cyclotron Resonance Mass Spectrometry Confirm External Binding Sites on the Minichromosomal Maintenance (MCM) Helicase, in J. Biol. Chem
This research was funded by the following grants: G.S. Boebinger (NSF DMR-1157490); M. A. Trakselis (American Cancer Society RSG-11-049-01-DMC )
For more information, contact Alan Marshall.