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Conjugative Mating Assays for Sequence-specific Analysis of Transfer Proteins Involved in Bacterial Conjugation
Published on: January 4, 2017
Structure of TrwB, a gatekeeper in bacterial conjugation
1Institut de Biologia Molecular de Barcelona, C.S.I.C., c/Jordi Girona, 18-26, 08034 Barcelona, Spain. xgrcri@ibmb.csic.es
The International Journal of Biochemistry & Cell Biology
|July 20, 2001
Summary
Bacterial conjugation involves DNA transfer via proteins like TrwB, crucial for spreading genetic information, including antibiotic resistance. This study reveals TrwB
Area of Science:
- Microbiology
- Molecular Biology
- Structural Biology
Background:
- Bacterial conjugation facilitates DNA transfer between cells, a key mechanism for spreading genetic traits, notably antibiotic resistance.
- Integral inner membrane DNA-binding proteins, such as TrwB in the E. coli R388 system, are essential for mediating DNA passage during conjugation.
- The process involves a type IV secretion system, forming the mating apparatus for inter-bacterial or trans-kingdom gene transfer.
Purpose of the Study:
- To elucidate the structural and functional characteristics of the TrwB protein, a key component of the bacterial conjugation machinery.
- To understand how TrwB facilitates the coupling of single-strand DNA for transfer between bacterial cells.
- To explore the structural similarities between TrwB and other DNA-processing proteins and energy-transducing ATPases.
Main Methods:
- Structural analysis of the TrwB protein, likely involving techniques like X-ray crystallography or cryo-electron microscopy.
- Biochemical assays to determine the DNA-binding and coupling activities of TrwB.
- Comparative structural analysis to identify similarities with proteins like RecA, DNA ring helicases, and F(1)-ATPase.
Main Results:
- The TrwB protein forms a homohexameric structure with an overall shape resembling F(1)-ATPase.
- Each TrwB protomer comprises a nucleotide-binding domain (alpha/beta topology) and an all-alpha domain.
- A central channel, approximately 20 angstroms wide, spans the hexamer, potentially facilitating DNA transport across cellular compartments.
Conclusions:
- TrwB's hexameric structure and central channel suggest a role in DNA translocation during conjugation.
- Structural homology to RecA and F(1)-ATPase implies conserved mechanisms in DNA processing and energy transduction.
- Understanding TrwB's structure provides insights into the molecular mechanisms of bacterial gene transfer and potential targets for intervention.
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