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A Visual Assay to Monitor T6SS-mediated Bacterial Competition

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Coupling factors in macromolecular type-IV secretion machineries.

F X Gomis-Rüth¹, M Solà, F de la Cruz

¹Institut de Biologia Molecular de Barcelona, C.S.I.C., c/ Jordi Girona, 18-26, E-08034 Barcelona, Spain. xgrcri@ibmb.csic.es

Current Pharmaceutical Design

|May 12, 2004

Summary

Type IV secretion systems (T4SSs) are crucial bacterial protein complexes. They facilitate DNA transfer, aiding antibiotic resistance spread, and are vital for various bacterial interactions and virulence.

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Conjugative Mating Assays for Sequence-specific Analysis of Transfer Proteins Involved in Bacterial Conjugation

Conjugative Mating Assays for Sequence-specific Analysis of Transfer Proteins Involved in Bacterial Conjugation

Published on: January 4, 2017

Area of Science:

Microbiology
Molecular Biology
Bacterial Pathogenesis

Background:

Type IV secretion systems (T4SSs) are complex bacterial machines essential for transferring molecules across cell membranes.
These systems are involved in diverse processes including bacterial conjugation, plant pathogenesis (e.g., Agrobacterium), toxin secretion (e.g., Bordetella, Helicobacter), and virulence factor translocation in pathogens like Legionella.
T4SSs play a significant role in the dissemination of antibiotic resistance genes through conjugative DNA delivery.

Purpose of the Study:

To elucidate the structure and function of type IV coupling proteins (T4CPs) within T4SSs.
To understand the role of T4CPs in connecting macromolecular secretion substrates to the transport conduit.
To explore potential mechanisms of T4CP action, including coupling, DNA pumping, or injection.

Main Methods:

Comparative analysis of T4SS components with known protein families like Vir proteins and SpoIIIE/FtsK.
Structural and functional characterization of T4CPs, using TrwB from E. coli and VirD4 from Agrobacterium as prototypes.
Investigation of T4CP localization within the donor cell near the secretion machinery.

Main Results:

T4SSs are composed of 10-15 proteins, traversing both bacterial membranes and the periplasm.
T4CPs, such as TrwB, are integral inner-membrane proteins essential for linking secretion substrates to the T4SS conduit.
T4CPs share homology with DNA-processing proteins, suggesting roles in DNA transport during conjugation.

Conclusions:

T4CPs are critical components of T4SSs, mediating substrate recognition and transfer.
The structural and functional similarities of T4CPs to DNA-related proteins suggest diverse roles in DNA transport and secretion.
Understanding T4CPs provides insights into bacterial conjugation, virulence, and the spread of antimicrobial resistance.