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-Structure paper
タイトル | Structural and biophysical analysis of a tripartite ATP-independent periplasmic (TRAP) transporter. |
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ジャーナル・号・ページ | Elife, Vol. 12, Year 2024 |
掲載日 | 2024年2月13日 |
著者 | Michael J Currie / James S Davies / Mariafrancesca Scalise / Ashutosh Gulati / Joshua D Wright / Michael C Newton-Vesty / Gayan S Abeysekera / Ramaswamy Subramanian / Weixiao Y Wahlgren / Rosmarie Friemann / Jane R Allison / Peter D Mace / Michael D W Griffin / Borries Demeler / Soichi Wakatsuki / David Drew / Cesare Indiveri / Renwick C J Dobson / Rachel A North / |
PubMed 要旨 | 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 ...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. |
リンク | Elife / PubMed:38349818 / PubMed Central |
手法 | EM (単粒子) |
解像度 | 2.99 - 3.36 Å |
構造データ | EMDB-41265, PDB-8thi: EMDB-41266, PDB-8thj: |
化合物 | ChemComp-PGT: ChemComp-NA: ChemComp-PTY: |
由来 |
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キーワード | TRANSPORT PROTEIN / Sugar transport / sialic acid / TRAP transporter / secondary active transport / ion transporter superfamily |