ジャーナル: Nat Commun / 年: 2022 タイトル: Cryo-EM structures of a LptDE transporter in complex with Pro-macrobodies offer insight into lipopolysaccharide translocation. 著者: Mathieu Botte / Dongchun Ni / Stephan Schenck / Iwan Zimmermann / Mohamed Chami / Nicolas Bocquet / Pascal Egloff / Denis Bucher / Matilde Trabuco / Robert K Y Cheng / Janine D Brunner / ...著者: Mathieu Botte / Dongchun Ni / Stephan Schenck / Iwan Zimmermann / Mohamed Chami / Nicolas Bocquet / Pascal Egloff / Denis Bucher / Matilde Trabuco / Robert K Y Cheng / Janine D Brunner / Markus A Seeger / Henning Stahlberg / Michael Hennig / 要旨: Lipopolysaccharides are major constituents of the extracellular leaflet in the bacterial outer membrane and form an effective physical barrier for environmental threats and for antibiotics in Gram- ...Lipopolysaccharides are major constituents of the extracellular leaflet in the bacterial outer membrane and form an effective physical barrier for environmental threats and for antibiotics in Gram-negative bacteria. The last step of LPS insertion via the Lpt pathway is mediated by the LptD/E protein complex. Detailed insights into the architecture of LptDE transporter complexes have been derived from X-ray crystallography. However, no structure of a laterally open LptD transporter, a transient state that occurs during LPS release, is available to date. Here, we report a cryo-EM structure of a partially opened LptDE transporter in complex with rigid chaperones derived from nanobodies, at 3.4 Å resolution. In addition, a subset of particles allows to model a structure of a laterally fully opened LptDE complex. Our work offers insights into the mechanism of LPS insertion, provides a structural framework for the development of antibiotics targeting LptD and describes a highly rigid chaperone scaffold to enable structural biology of challenging protein targets.