Related Experiment Video
Updated: Jul 30, 2026
10:23
Self-assembly of Complex Two-dimensional Shapes from Single-stranded DNA Tiles
Published on: May 8, 2015
Structural basis for DNA bridging by barrier-to-autointegration factor.
Christina Marchetti Bradley1, Donald R Ronning, Rodolfo Ghirlando
1Laboratory of Molecular Biology, National Institute of Diabetes & Digestive & Kidney Diseases, US National Institutes of Health (NIH), 5 Center Drive, Bethesda, Maryland 20892, USA.
Nature Structural & Molecular Biology
|September 13, 2005
Summary
Barrier-to-autointegration factor (BAF) binds DNA without a specific sequence, which is vital for its function. The crystal structure shows BAF uses helix-hairpin-helix motifs to bridge DNA, revealing its mechanism.
Area of Science:
- Structural biology
- Molecular biology
- Virology
Background:
- Barrier-to-autointegration factor (BAF) plays a key role in retroviral integration.
- BAF's ability to bind and bridge DNA is essential for its biological functions.
- Understanding BAF's DNA-binding mechanism is crucial for retroviral research.
Purpose of the Study:
- To elucidate the structural basis of BAF's DNA binding and bridging activity.
- To investigate the role of specific BAF motifs in DNA interaction.
- To provide insights into BAF's function in retroviral integration.
Main Methods:
- X-ray crystallography to determine the structure of BAF bound to DNA.
- Structural analysis of BAF-DNA complex to identify key interaction interfaces.
- Biochemical assays to confirm DNA binding and bridging properties.
Main Results:
- The crystal structure of the barrier-to-autointegration factor (BAF) in complex with DNA was determined.
- BAF forms a dimer that bridges DNA molecules.
- Two pairs of helix-hairpin-helix motifs on opposite surfaces of the BAF dimer are responsible for DNA bridging.
- BAF binds DNA in a sequence-independent manner without conformational changes.
Conclusions:
- The determined structure reveals the molecular mechanism by which BAF bridges DNA.
- The helix-hairpin-helix motifs are critical for BAF's DNA-bridging function.
- This structural insight aids in understanding BAF's role in retroviral integration and other cellular processes.
Related Concept Videos
01:02The DNA Replication Fork
An organism’s genome needs to be duplicated in an efficient and error-free manner for its growth and survival. The replication fork is a Y-shaped active region where two strands of DNA are separated and replicated continuously. The coupling of DNA unzipping and complementary strand synthesis is a characteristic feature of a replication fork. Organisms with small circular DNA, such as E. coli, often have a single origin of replication; therefore, they have only two replication forks, one in...
02:04Fixing Double-strand Breaks
The double-stranded structure of DNA has two major advantages. First, it serves as a safe repository of genetic information where one strand serves as the back-up in case the other strand is damaged. Second, the double-helical structure can be wrapped around proteins called histones to form nucleosomes, which can then be tightly wound to form chromosomes. This way, DNA chains up to 2 inches long can be contained within microscopic structures in a cell. A double-stranded break not only damages...
02:31Homologous Recombination
The basic reaction of homologous recombination (HR) involves two chromatids that contain DNA sequences sharing a significant stretch of identity. One of these sequences uses a strand from another as a template to synthesize DNA in an enzyme-catalyzed reaction. The final product is a novel amalgamation of the two substrates. To ensure an accurate recombination of sequences, HR is restricted to the S and G2 phases of the cell cycle. At these stages, the DNA has been replicated already and the...
01:03Single-Strand DNA Binding Proteins
For successful DNA replication, the unwinding of double-stranded DNA must be accompanied by stabilization and protection of the separated single strands of the DNA. This crucial task is performed by single-strand DNA-binding (SSB) proteins. They bind to the DNA in a sequence-independent manner, which means that the nitrogenous bases of the DNA need not be present in a specific order for binding of SSB proteins to it. The binding of SSB proteins straightens single-stranded DNA (ssDNA) and makes...
01:02The DNA Replication Fork
An organism’s genome needs to be duplicated in an efficient and error-free manner for its growth and survival. The replication fork is a Y-shaped active region where two strands of DNA are separated and replicated continuously. The coupling of DNA unzipping and complementary strand synthesis is a characteristic feature of a replication fork. Organisms with small circular DNA, such as E. coli, often have a single origin of replication; therefore, they have only two replication forks, one in...
02:04Fixing Double-strand Breaks
The double-stranded structure of DNA has two major advantages. First, it serves as a safe repository of genetic information where one strand serves as the back-up in case the other strand is damaged. Second, the double-helical structure can be wrapped around proteins called histones to form nucleosomes, which can then be tightly wound to form chromosomes. This way, DNA chains up to 2 inches long can be contained within microscopic structures in a cell. A double-stranded break not only damages...