Integration host factor

1OWG IHF complex

Integration host factor (IHF) is a DNA-binding protein found in bacteria that plays a crucial role in various cellular processes, including DNA replication, transcription, and recombination. IHF is a member of the histone-like proteins family and is known for its ability to induce sharp bends in DNA, facilitating the formation of higher-order nucleoprotein structures.

Structure and Function

IHF is a heterodimer composed of two subunits, IHFα and IHFβ, which are encoded by the ihfA and ihfB genes, respectively. The protein binds to specific DNA sequences, causing the DNA to bend by approximately 160 degrees. This bending is essential for the proper functioning of various DNA transactions, as it brings distant regions of the DNA into close proximity, enabling interactions between proteins bound at these sites.

Role in DNA Replication

In DNA replication, IHF is involved in the initiation process. It binds to the origin of replication and helps in the assembly of the replisome, the complex of proteins responsible for DNA synthesis. By bending the DNA, IHF facilitates the unwinding of the double helix, allowing the replication machinery to access the template strands.

Role in Transcription

IHF also plays a significant role in transcription regulation. It acts as an architectural factor, assisting in the formation of transcriptional complexes by bringing together regulatory proteins and RNA polymerase. This is particularly important in the regulation of genes involved in stress response and virulence in pathogenic bacteria.

Role in Recombination

In the process of genetic recombination, IHF is essential for the integration of foreign DNA into the host genome. It is involved in the site-specific recombination events mediated by recombinase enzymes, such as those occurring during the integration of bacteriophage DNA into the bacterial chromosome.

Related Proteins

IHF is related to other DNA-bending proteins, such as HU and Fis, which also play roles in DNA architecture and regulation. These proteins share structural similarities and often work in concert to modulate DNA topology and facilitate various cellular processes.

Research and Applications

Research on IHF has provided insights into the mechanisms of DNA bending and its impact on cellular functions. Understanding the role of IHF and related proteins can lead to advancements in biotechnology and medicine, particularly in the development of novel antimicrobial strategies targeting bacterial DNA transactions.

See Also

• DNA-binding protein
• Histone-like proteins
• DNA replication
• Transcription (biology)
• Genetic recombination
• Replisome
• RNA polymerase
• Stress response
• Virulence
• Bacteriophage
• Recombinase