Crystal Structure of a Group I Energy Coupling Factor Vitamin Transporter S Component in Complex with Its Cognate Substrate. Issue 7 (21st July 2016) - Josts, Inokentijs
Summary: Energy coupling factor (ECF) transporters are responsible for the uptake of essential scarce nutrients in prokaryotes. This ATP-binding cassette transporter family comprises two subgroups that share a common architecture forming a tripartite membrane protein complex consisting of a translocation component and ATP hydrolyzing module and a substrate-capture (S) component. Here, we present the crystal structure of YkoE from Bacillus subtilis, the S component of the previously uncharacterized group I ECF transporter YkoEDC. Structural and biochemical analyses revealed the constituent residues of the thiamine-binding pocket as well as an unexpected mode of vitamin recognition. In addition, our experimental and bioinformatics data demonstrate major differences between YkoE and group II ECF transporters and indicate how group I vitamin transporter S components have diverged from other group I and group II ECF transporters. Graphical Abstract: Highlights: The crystal structure of a group I ECF transporter S component was determined The thiamine-bound structure was determined in lipidic environment The structure reveals major differences to group II S components CGMD simulations indicate the orientation of the protein in the membrane Abstract : Josts et al. determined the crystal structure of a substrate-bound group I ECF vitamin transporter S component, which revealed major differences to group II S components and indicates how group I S components have diverged from other group I and II ECF transporters.