Weak Interactions between Salmonella enterica FlhB and Other Flagellar Export Apparatus Proteins Govern Type III Secretion Dynamics
| Autor: | Yukio Furukawa, Stephanie A. Hill, Keiichi Namba, Tohru Minamino, Jonathan L. McMurry, Joshua W. Francis, Katy A. Helms |
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| Rok vydání: | 2015 |
| Předmět: |
Immunoblotting
lcsh:Medicine Plasma protein binding Flagellum Biology Flik Protein–protein interaction Adenosine Triphosphate Bacterial Proteins Computer Simulation lcsh:Science Integral membrane protein Multidisciplinary lcsh:R Membrane Proteins Salmonella enterica Transport protein Cell biology Kinetics Protein Transport Proton-Translocating ATPases Transmembrane domain Membrane protein Flagella Mutation lcsh:Q Protein Multimerization Algorithms Research Article Protein Binding |
| Zdroj: | PLoS ONE, Vol 10, Iss 8, p e0134884 (2015) PLoS ONE |
| ISSN: | 1932-6203 |
| DOI: | 10.1371/journal.pone.0134884 |
| Popis: | The bacterial flagellum contains its own type III secretion apparatus that coordinates protein export with assembly at the distal end. While many interactions among export apparatus proteins have been reported, few have been examined with respect to the differential affinities and dynamic relationships that must govern the mechanism of export. FlhB, an integral membrane protein, plays critical roles in both export and the substrate specificity switching that occurs upon hook completion. Reported herein is the quantitative characterization of interactions between the cytoplasmic domain of FlhB (FlhBC) and other export apparatus proteins including FliK, FlhAC and FliI. FliK and FlhAC bound with micromolar affinity. KD for FliI binding in the absence of ATP was 84 nM. ATP-induced oligomerization of FliI induced kinetic changes, stimulating fast-on, fast-off binding and lowering affinity. Full length FlhB purified under solubilizing, nondenaturing conditions formed a stable dimer via its transmembrane domain and stably bound FliH. Together, the present results support the previously hypothesized central role of FlhB and elucidate the dynamics of protein-protein interactions in type III secretion. |
| Databáze: | OpenAIRE |
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