8THI

Cryo-EM structure of the Tripartite ATP-independent Periplasmic (TRAP) transporter SiaQM from Haemophilus influenzae (parallel dimer)

8THI の概要

• エントリーDOI: 10.2210/pdb8thi/pdb
• EMDBエントリー: 41265 41266
• 分子名称: Sialic acid TRAP transporter permease protein SiaT, (1S)-2-{[{[(2R)-2,3-DIHYDROXYPROPYL]OXY}(HYDROXY)PHOSPHORYL]OXY}-1-[(PALMITOYLOXY)METHYL]ETHYL STEARATE, SODIUM ION (3 entities in total)
• 機能のキーワード: sugar transport, sialic acid, trap transporter, secondary active transport, ion transporter superfamily, transport protein
• 由来する生物種: Haemophilus influenzae Rd KW20
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 145641.65

構造登録者

Davies, J.S.,Currie, M.C.,Dobson, R.C.J.,North, R.A. (登録日: 2023-07-16, 公開日: 2023-11-22, 最終更新日: 2025-05-21)

主引用文献

Currie, M.J.,Davies, J.S.,Scalise, M.,Gulati, A.,Wright, J.D.,Newton-Vesty, M.C.,Abeysekera, G.S.,Subramanian, R.,Wahlgren, W.Y.,Friemann, R.,Allison, J.R.,Mace, P.D.,Griffin, M.D.W.,Demeler, B.,Wakatsuki, S.,Drew, D.,Indiveri, C.,Dobson, R.C.J.,North, R.A.
Structural and biophysical analysis of a Haemophilus influenzae tripartite ATP-independent periplasmic (TRAP) transporter.
Elife, 12:-, 2024

PubMed Abstract: Tripartite ATP-independent periplasmic (TRAP) transporters are secondary-active transporters that receive their substrates via a soluble-binding protein to move bioorganic acids across bacterial or archaeal cell membranes. Recent cryo-electron microscopy (cryo-EM) structures of TRAP transporters provide a broad framework to understand how they work, but the mechanistic details of transport are not yet defined. Here we report the cryo-EM structure of the -acetylneuraminate TRAP transporter (SiaQM) at 2.99 Å resolution (extending to 2.2 Å at the core), revealing new features. The improved resolution (the previous SiaQM structure is 4.7 Å resolution) permits accurate assignment of two Na sites and the architecture of the substrate-binding site, consistent with mutagenic and functional data. Moreover, rather than a monomer, the SiaQM structure is a homodimer. We observe lipids at the dimer interface, as well as a lipid trapped within the fusion that links the SiaQ and SiaM subunits. We show that the affinity () for the complex between the soluble SiaP protein and SiaQM is in the micromolar range and that a related SiaP can bind SiaQM. This work provides key data that enhances our understanding of the 'elevator-with-an-operator' mechanism of TRAP transporters.

PubMed: 38349818
DOI: 10.7554/eLife.92307

実験手法

ELECTRON MICROSCOPY (3.36 Å)