Comparative Analysis of the Dynamics of the Histidine ABC Transporter and the ECF-Type Biotin Transporter


Canonical ABC transport systems mediating the uptake of solutes in prokaryotes are composed of an extracytoplasmic solute binding protein, two pore-forming subunits and an ATPase dimer. Our current knowledge on the transport mechanism is largely based on structural and functional analysis of the maltose transporter of E. coli/Salmonella. Due to some unique features of this system it is questionable whether the derived transport model holds for other type I ABC importers. Thus, we will study conformational changes of the similarly well-characterized histidine transporter, HisJ/LAO-QMP2, of S. typhimurium. Based on results obtained in the previous funding period, we will focus on investigating changes in affinity of the transporter for its cognate binding protein during the transport cycle using microscale thermophoresis and surface plasmon resonance as experimental tools. These studies are aimed to better understand conformational changes of the transmembrane domains that are initiated by the binding protein and in turn trigger ATP hydrolysis at the opposite side of the membrane. Furthermore, by taking advantage of our expertise on canonical ABC importers, we will study conformational changes of the BioYMN transporter, a member of the newly discovered subfamily of ECF-transporters. In particular, we will apply site-directed chemical cross-linking on cysteine variants incorporated into nano-discs to elucidate the dynamics of the ATPase BioM and the interaction of BioM and BioN dependent on substrate and/or nucleotides.


Principal Investigators
Schneider, Erwin Prof. Dr. rer. nat. (Details) (Physiology of Microorganisms)

Duration of Project
Start date: 04/2013
End date: 12/2016

Publications
Eckey, V., Landmesser, H., and Schneider, E. (2010) Studying subunit-subunit interactions in a bacterial ABC transporter by in vitro-assembly. Biochem. Biophys. Acta 1798, 250-1253. Eckey, V., Weidlich, W., Landmesser, H., Bergmann, U., and Schneider, E. (2010) The second extracellular loop of pore-forming subunits of ATP-binding cassette transporters for basic amino acids plays a crucial role in interaction with the cognate solute binding protein(s). J. Bacteriol. 192, 2150-2159. Eitinger, T., Rodionov, D.A., Grote, M., and Schneider, E. (2011) Canonical and ECF-type ATP-binding cassette importers in prokaryotes: diversity in modular organisation and cellular functions. FEMS Microbiol. Rev. 35, 3-67. Licht, A., and Schneider, E. (2011) ATP binding cassette systems: structures, mechanisms, and functions. Cent. Eur. J. Biol. 6, 785-801. Schneider, E., Eckey, V., Weidlich, D., Wiesemann, N., Vahedi-Faridi, A., Thaben, P., and Saenger, W. (2012) Receptor-transporter interactions of canonical ATP-binding cassette import systems in prokaryotes. Eur. J. Cell Biol. 91, 311-317.

Last updated on 2020-04-11 at 13:31