Related Experiment Video

Updated: Aug 15, 2026

High Resolution Electron Microscopy of the Helicobacter pylori Cag Type IV Secretion System Pili Produced in Varying Conditions of Iron Availability
09:05

High Resolution Electron Microscopy of the Helicobacter pylori Cag Type IV Secretion System Pili Produced in Varying Conditions of Iron Availability

Published on: November 21, 2014

Molecular basis of the interaction between the flagellar export proteins FliI and FliH from Helicobacter pylori

Michael C Lane1, Paul W O'Toole, Stanley A Moore

  • 1Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada.

The Journal of Biological Chemistry
|November 2, 2005
PubMed

Insights

Helicobacter pylori flagellar protein export involves FliI ATPase and FliH inhibitor. Their interaction is mediated by FliI

Area of Science:

  • Microbiology
  • Molecular Biology
  • Biochemistry

Background:

  • Bacterial flagellar assembly is crucial for motility and virulence.
  • The flagellar protein export system requires energy supplied by an ATPase (FliI) and is regulated by an inhibitor (FliH).
  • Understanding the interaction between FliI and FliH is key to elucidating flagellar export regulation in pathogens like Helicobacter pylori.

Purpose of the Study:

  • To investigate the molecular mechanisms underlying the interaction between FliI and FliH in Helicobacter pylori.
  • To identify the specific regions and residues of FliI involved in binding to FliH.
  • To explore the functional implications of the FliI-FliH interaction, potentially revealing FliH's role.

Main Methods:

  • Bioinformatic analysis to predict protein structures and interactions.
  • Biochemical assays to confirm protein interactions and binding sites.
  • Deletion and scanning mutagenesis of FliI to pinpoint critical residues for FliH interaction.

Main Results:

  • Residues 1-18 of FliI form an alpha-helix upon binding to FliH.
  • The N-terminal 18 residues of FliI are essential for FliI/FliH interaction.
  • A hydrophobic cluster within the N-terminal 10 residues of FliI is critical for binding FliH, suggesting FliH acts as a molecular stator.

Conclusions:

  • The N-terminal alpha-helix of FliI is vital for its interaction with FliH in Helicobacter pylori.
  • The identified interaction mechanism shares similarities with F1-ATPase subunit interactions.
  • FliH likely functions as a molecular stator in the bacterial flagellar protein export system.

More Related Videos

Investigating Flagella-Driven Motility in Escherichia coli by Applying Three Established Techniques in a Series07:59

Investigating Flagella-Driven Motility in Escherichia coli by Applying Three Established Techniques in a Series

Published on: May 10, 2020

Related Concept Videos

Fimbriae, Pili, and Axial Filaments01:28

Fimbriae, Pili, and Axial Filaments

Fimbriae and pili are specialized bacterial surface structures that play pivotal roles in adhesion, genetic exchange, and motility. Composed primarily of pilin protein, these hairlike appendages are crucial for bacterial survival and pathogenicity in various environments.Fimbriae: Adhesion and PathogenicityFimbriae are fine, filamentous structures measuring 2–10 nanometers in diameter and are densely distributed on the bacterial cell surface. They facilitate bacterial adhesion to abiotic...
Flagella and Motility in Bacteria01:18

Flagella and Motility in Bacteria

Flagella are specialized, thread-like structures that extend from a bacteria's cell envelope. They play a crucial role in motility and chemotaxis. Their structural organization and functioning exemplify sophisticated biological engineering, enabling bacterial survival and adaptability in diverse environments.Structure of the FlagellumA bacterial flagellum consists of three key components: the filament, the hook, and basal body. The filament, a long, helical structure composed of repeating...
Cytoskeletal Proteins in Bacteria01:29

Cytoskeletal Proteins in Bacteria

Bacterial cells were initially considered simple, randomly organized structures lacking a cytoskeleton. However, the discovery of cytoskeleton homologs in bacteria led to the change of this opinion. Bacterial cytoskeletal filaments regulate the cell shape, cell polarity, cell division, and partitioning of plasmids during cell division. It was later discovered that bacterial cytoskeletal proteins, mainly actin and tubulin homologs, are diverse compared to their eukaryotic counterparts. On the...
Mechanism of Filopodia Formation01:39

Mechanism of Filopodia Formation

Filopodia are thin, actin-rich cellular protrusions that play an important role in many fundamental cellular functions. They vary in their occurrence, length, and positioning in different cell types, suggesting their diverse roles.
Their main function is to guide migrating cells during normal tissue morphogenesis or cancer metastasis by recognizing and making initial contacts with the extracellular matrix. However, they can also act as stationary cell anchors or help to establish communication...
Coordination of Gene Expression Processes in Bacteria01:29

Coordination of Gene Expression Processes in Bacteria

The DNA replication, transcription, and translation processes are intricately coupled in bacteria, allowing efficient gene expression and rapid protein synthesis. While this physical and functional coordination is advantageous, it introduces challenges that bacteria overcome through specific regulatory mechanisms.Coupling of Replication, Transcription, and TranslationThe coupling of replication, transcription, and translation is a hallmark of bacterial gene expression. As the replisome unwinds...
Formation of Intermediate Filaments00:57

Formation of Intermediate Filaments

Intermediate filaments are cytoskeletal proteins with higher tensile strength and flexibility than microfilaments and microtubules. Unlike the other two cytoskeletal proteins, intermediate filament formation lacks the enzymatic activity to hydrolyze nucleotides like ATP and GTP to generate energy for polymerization. Therefore, the formation of intermediate filaments is multistep self-assembly. The involvement of any accessory proteins in intermediate filament formation has not yet been reported.