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Updated: Jun 12, 2026
Microscopy-based Assays for High-throughput Screening of Host Factors Involved in Brucella Infection of Hela Cells
Published on: August 5, 2016
Structural Characterization of the Type IV Secretion System in Brucella melitensis for Virtual Screening-Based
Jahnvi Kapoor1, Amisha Panda1, Raman Rajagopal2
1Protein Biology Lab, Department of Zoology, University of Delhi, Delhi110007, India.
Abstract:
Brucellosis is a globally important zoonotic disease caused by Brucella melitensis, the most virulent and clinically significant species affecting both humans and livestock. Unlike many Gram-negative pathogens, B. melitensis lacks conventional virulence factors and instead relies on specialized systems such as the Type IV Secretion System (T4SS) for the secretion of effector proteins. In this study, an integrated computational pipeline was implemented to identify, model, and assemble the T4SS components encoded by virB operon from the complete B. melitensis proteome. Template-based modeling strategies were employed to model T4SS subcomplexes, referencing crystallographic data from E. coli T4SS. Structural superposition with E. coli homologues revealed highly conserved architecture despite only 30-50% sequence identity. Stereochemical validation confirmed favorable interactions among most VirB protein pairs, and membrane insertion analysis corroborated the spatial orientation of the modeled T4SS. Potential of T4SS as a drug target was explored by targeting dimeric interface of VirB11 ATPase to disrupt protein-protein interactions. Virtual screening of compounds from DrugBank revealed compounds with docking score ≤-7.0 kcal/mol, and ADMET screening yielded three promising candidates─Ezetimibe (Drug ID: DB00973), Chlordiazepoxide (Drug ID: DB00475), and Alloin (Drug ID: DB15477). MM-GBSA analysis and molecular dynamics simulation supported favorable protein-ligand interactions. Collectively, these findings provide new insights into the architecture of B. melitensis T4SS and identify three potential drug molecules targeting T4SS. This supports FDA-approved drug repurposing as an effective strategy for antivirulence therapy against Brucellosis.
Insights
Brucellosis treatment can be advanced by targeting the Type IV Secretion System (T4SS) in Brucella melitensis. This study modeled the T4SS and identified three drug candidates for potential repurposing against this zoonotic disease.
Area of Science:
- Microbiology
- Structural Biology
- Computational Biology
Background:
- Brucellosis is a significant zoonotic disease caused by Brucella melitensis.
- Brucella melitensis lacks conventional virulence factors, relying on the Type IV Secretion System (T4SS) for pathogenesis.
Purpose of the Study:
- To computationally identify, model, and assemble the T4SS components of Brucella melitensis.
- To explore the T4SS as a drug target for Brucellosis therapy.
Main Methods:
- Integrated computational pipeline for T4SS identification and modeling.
- Template-based modeling using E. coli T4SS crystallographic data.
- Virtual screening and molecular dynamics simulations for drug discovery.
Main Results:
- Modeled Brucella melitensis T4SS exhibits conserved architecture with E. coli homologues.
- Identified three potential drug candidates (Ezetimibe, Chlordiazepoxide, Alloin) targeting VirB11 ATPase.
- Confirmed favorable protein-ligand interactions and stability through simulations.
Conclusions:
- The study provides structural insights into the Brucella melitensis T4SS.
- Identified drug candidates offer a promising avenue for antivirulence therapy against Brucellosis.
- Drug repurposing presents an effective strategy for Brucellosis treatment.
