National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
R35GM128777
米国
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
1K99GM157496-01
米国
Other private
The Charles H. Revson Foundation
引用
ジャーナル: bioRxiv / 年: 2025 タイトル: LetA defines a structurally distinct transporter family involved in lipid trafficking. 著者: Cristina C Santarossa / Yupeng Li / Sara Yousef / Hale S Hasdemir / Carlos C Rodriguez / Max B Haase / Minkyung Baek / Nicolas Coudray / John G Pavek / Kimber N Focke / Annika L Silverberg / ...著者: Cristina C Santarossa / Yupeng Li / Sara Yousef / Hale S Hasdemir / Carlos C Rodriguez / Max B Haase / Minkyung Baek / Nicolas Coudray / John G Pavek / Kimber N Focke / Annika L Silverberg / Carmelita Bautista / Johannes Yeh / Michael T Marty / David Baker / Emad Tajkhorshid / Damian C Ekiert / Gira Bhabha 要旨: Membrane transport proteins translocate diverse cargos, ranging from small sugars to entire proteins, across cellular membranes. A few structurally distinct protein families have been described that ...Membrane transport proteins translocate diverse cargos, ranging from small sugars to entire proteins, across cellular membranes. A few structurally distinct protein families have been described that account for most of the known membrane transport processes. However, many membrane proteins with predicted transporter functions remain uncharacterized. We determined the structure of LetAB, a phospholipid transporter involved in outer membrane integrity, and found that LetA adopts a distinct architecture that is structurally and evolutionarily unrelated to known transporter families. LetA functions as a pump at one end of a ~225 Å long tunnel formed by its binding partner, MCE protein LetB, creating a pathway for lipid transport between the inner and outer membranes. Unexpectedly, the LetA transmembrane domains adopt a fold that is evolutionarily related to the eukaryotic tetraspanin family of membrane proteins, including TARPs and claudins. LetA has no detectable homology to known transport proteins, and defines a new class of membrane transporters. Through a combination of deep mutational scanning, molecular dynamics simulations, AlphaFold-predicted alternative states, and functional studies, we present a model for how the LetA-like family of membrane transporters may use energy from the proton-motive force to drive the transport of lipids across the bacterial cell envelope.
Chain - Source name: PDB / Chain - Initial model type: experimental model 詳細: The initial model consisted of the complete biological assembly for PDB entry 6V0F
詳細
Model was fit as a rigid-body into the individual map using Chimera. Real space refinement was carried out in PHENIX. Models were then manually inspected and adjusted in Coot. Iterative rounds of model building and refinement were performed.