Multidrug resistance is a serious threat to public health. Proton motive force-driven antiporters from the major facilitator superfamily (MFS) constitute a major group of multidrug-resistance transporters. Currently, no reports on crystal structures of MFS antiporters in complex with their substrates exist. The E. coli MdfA transporter is a well-studied model system for biochemical analyses of multidrug-resistance MFS antiporters. Here, we report three crystal structures of MdfA-ligand complexes at resolutions up to 2.0 ?, all in the inward-facing conformation. The substrate-binding site sits proximal to the conserved acidic residue, D34. Our mutagenesis studies support the structural observations of the substrate-binding mode and the notion that D34 responds to substrate binding by adjusting its protonation status. Taken together, our data unveil the substrate-binding mode of MFS antiporters and suggest a mechanism of transport via this group of transporters.
Kinases play extensive and important roles in signal transduction and co-ordination of complex functions. Currently, about 300 kinase inhibitors have been approved for marketing, among which receptor tyrosine kinase (RTK) inhibitors are the main ones. Medicilon provides high-quality kinase profile screening and has one-stop kinase research services from assay development, high-throughput screening to selectivity analysis. In addition, Medicilon provides many other enzyme activity screens. Wide Variety Provides 200+ in vitro enzymatic detection methods; 100+ kinases, including CTK, RTK, AGC, CMGC and other kinase families as well as important common mutations Project Flexibility Various types of plates for screening, such as 96 and 384; Multiple flexible kinase profiles, including TK kinase family, CDK kinase family, etc., to meet different customer customization needs. Various Methods Fluorescence detection; Chemiluminescence detection; Absorbance detection LanthaScr...
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