One way by which bacteria achieve antibiotics resistance is preventing drug access to its target molecule for example through an overproduction of multi-drug efflux pumps of the resistance nodulation division (RND) protein super family of which AcrAB-TolC in Escherichia coli is a prominent example. Although representing one of the best studied efflux systems, the question of how AcrB and TolC interact is still unclear as the available experimental data suggest that either both proteins interact in a tip to tip manner or do not interact at all but are instead connected by a hexamer of AcrA molecules. Addressing the question of TolC-AcrB interaction, we performed a series of 100 ns - 1 µs-molecular dynamics simulations of membrane-embedded TolC in presence of the isolated AcrB docking domain (AcrB(DD)). In 5/6 simulations we observe direct TolC-AcrB(DD) interaction that is only stable on the simulated time scale when both proteins engage in a tip to tip manner. At the same time we find TolC opening and closing freely on extracellular side while remaining closed at the inner periplasmic bottleneck region, suggesting that either the simulated time is too short or additional components are required to unlock TolC.
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http://dx.doi.org/10.1016/j.bbamem.2016.03.029 | DOI Listing |
Mol Divers
January 2025
Department of Biochemistry, University of Delhi South Campus, Benito Juarez Road, Dhaula Kuan, New Delhi, 110021, India.
Nanobodies or variable antigen-binding domains (VH) derived from heavy chain-only antibodies (HcAb) occurring in the Camelidae family offer certain superior physicochemical characteristics like enhanced stability, solubility, and low immunogenicity compared to conventional antibodies. Their efficient antigen-binding capabilities make them a preferred choice for next-generation small biologics. In the present work, we design an anti-SARS-CoV-2 bi-paratopic nanobody drug conjugate by screening a nanobody database.
View Article and Find Full Text PDFActa Pharmacol Sin
January 2025
Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, 221004, China.
Patients suffering epilepsy caused by the gain-of-function mutants of the hKCNT1 potassium channels are drug refractory. In this study, we cloned a novel human KCNT1B channel isoform using the brain cDNA library and conducted patch-clamp and molecular docking analyses to characterize the pharmacological properties of the hKCNT1B channel using thirteen drugs. Among cinchona alkaloids, we found that hydroquinine exerted the strongest blocking effect on the hKCNT1B channel, especially the F313L mutant.
View Article and Find Full Text PDFSci Rep
January 2025
Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, P.O. Box 2455, 11451, Riyadh, Saudi Arabia.
Polycyclic aromatic compounds (PACs) are pervasive environmental contaminants derived from diverse sources including pyrogenic (e.g., combustion processes), petrogenic (e.
View Article and Find Full Text PDFJ Med Virol
February 2025
Department of Microbiology, School of Basic Medicine, Air Force Military Medical University, Xi'an, China.
Virus budding is a critical step in the replication cycle of enveloped viruses, closely linked to viral spread, disease progression, and clinical outcomes. The budding of many enveloped RNA viruses is facilitated by the hijacking of the host endosomal sorting complex required for transport (ESCRT) proteins through viral late domains. These late domains are essential for progeny virus production and are highly conserved, making the interaction between late domains and host ESCRT proteins a potential target for the development of antiviral therapeutics.
View Article and Find Full Text PDFJ Cell Biol
April 2025
Department of Genetics and Cell Biology, College of Life Sciences, State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, China.
TBC1D20 deficiency causes Warburg Micro Syndrome in humans, characterized by multiple eye abnormalities, severe intellectual disability, and abnormal sexual development, but the molecular mechanisms remain unknown. Here, we identify TBC1D20 as a novel Rab11 GTPase-activating protein that coordinates vesicle transport and actin remodeling to regulate ciliogenesis. Depletion of TBC1D20 promotes Rab11 vesicle accumulation and actin deconstruction around the centrosome, facilitating the initiation of ciliogenesis even in cycling cells.
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