Oroxylin A inhibits hemolysis via hindering the self-assembly of α-hemolysin heptameric transmembrane pore.
Oroxylin A inhibits hemolysis via hindering the self-assembly of α-hemolysin heptameric transmembrane pore.
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DOI：
10.1371/journal.pcbi.1002869
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发表时间：
2013
影响因子：
4.3
通讯作者：
Deng X
中科院分区：
文献类型：
--
作者：
Dong J;Qiu J;Zhang Y;Lu C;Dai X;Wang J;Li H;Wang X;Tan W;Luo M;Niu X;Deng X
Alpha-hemolysin (α-HL) is a self-assembling, channel-forming toxin produced by most Staphylococcus aureus strains as a 33.2-kDa soluble monomer. Upon binding to a susceptible cell membrane, the monomer self-assembles to form a 232.4-kDa heptamer that ultimately causes host cell lysis and death. Consequently, α-HL plays a significant role in the pathogenesis of S. aureus infections, such as pneumonia, mastitis, keratitis and arthritis. In this paper, experimental studies show that oroxylin A (ORO), a natural compound without anti-S. aureus activity, can inhibit the hemolytic activity of α-HL. Molecular dynamics simulations, free energy calculations, and mutagenesis assays were performed to understand the formation of the α-HL-ORO complex. This combined approach revealed that the catalytic mechanism of inhibition involves the direct binding of ORO to α-HL, which blocks the conformational transition of the critical “Loop” region of the α-HL protein thereby inhibiting its hemolytic activity. This mechanism was confirmed by experimental data obtained from a deoxycholate-induced oligomerization assay. It was also found that, in a co-culture system with S. aureus and human alveolar epithelial (A549) cells, ORO could protect against α-HL-mediated injury. These findings indicate that ORO hinders the lytic activity of α-HL through a novel mechanism, which should facilitate the design of new and more effective antibacterial agents against S. aureus. The mechanism controlling protein-ligand interactions is one of the most important processes in rational drug design. X-ray crystallography is a traditional tool used to investigate the interaction of ligands and proteins in a complex. However, protein crystallography is inefficient, and the development of crystal technology and research remains unequally distributed. Thus, it seems impractical to explore the structure of the α-hemolysin-ORO monomer complex by crystallography. Therefore, we used molecular dynamics simulations to investigate the receptor-ligand interaction in the α-HL-ORO monomer complex. In this study, we found that oroxylin A (ORO), a natural compound with little anti-S. aureus activity, can inhibit the hemolytic activity of α-HL at low concentrations. Through molecular docking and molecular dynamics simulations, we determined the potential binding mode of the protein-ligand interaction. The data revealed that ORO directly binds to α-HL, an interaction that blacks the conformational transition of the critical “Loop” region in α-HL and thus prevents the formation of the α-HL heptameric transmembrane pore, which ultimately inhibits the hemolytic activity of α-HL. This mechanism was confirmed by experimental data. Furthermore, we demonstrated that ORO could protect against α-HL-mediated injury in human alveolar epithelial (A549) cells.
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影响因子：
5.5
作者：
Hess, Berk;Kutzner, Carsten;Lindahl, Erik
通讯作者：
Lindahl, Erik
影响因子：
3.5
作者：
Filomia, Federico;De Rienzo, Francesca;Menziani, M. Cristina
通讯作者：
Menziani, M. Cristina
影响因子：
3.4
作者：
Aksimentiev, A;Schulten, K
通讯作者：
Schulten, K
影响因子：
4.4
作者：
JORGENSEN, WL;CHANDRASEKHAR, J;KLEIN, ML
通讯作者：
KLEIN, ML
DOI：
10.1073/pnas.78.9.5475
发表时间：
1981-01-01
期刊：
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA-BIOLOGICAL SCIENCES
影响因子：
--
作者：
BHAKDI, S;FUSSLE, R;TRANUMJENSEN, J
通讯作者：
TRANUMJENSEN, J