4AIN

Crystal structure of BetP with asymmetric protomers.

4AIN の概要

• エントリーDOI: 10.2210/pdb4ain/pdb
• 関連するPDBエントリー: 2WIT
• 分子名称: GLYCINE BETAINE TRANSPORTER BETP, SODIUM ION, TRIMETHYL GLYCINE, ... (8 entities in total)
• 機能のキーワード: membrane protein, chemosensor and osmosensor, secondary transporter, sodium coupled transport, transmembrane, hyperosmotic stress
• 由来する生物種: CORYNEBACTERIUM GLUTAMICUM
• 細胞内の位置: Cell membrane; Multi-pass membrane protein: P54582
• タンパク質・核酸の鎖数: 3
• 化学式量合計: 175466.84

構造登録者

Koshy, C.,Ziegler, C.,Yildiz, O. (登録日: 2012-02-10, 公開日: 2012-06-06, 最終更新日: 2023-11-15)

主引用文献

Perez, C.,Koshy, C.,Yildiz, O.,Ziegler, C.
Alternating-Access Mechanism in Conformationally Asymmetric Trimers of the Betaine Transporter Betp.
Nature, 490:126-, 2012

PubMed Abstract: Betaine and Na(+) symport has been extensively studied in the osmotically regulated transporter BetP from Corynebacterium glutamicum, a member of the betaine/choline/carnitine transporter family, which shares the conserved LeuT-like fold of two inverted structural repeats. BetP adjusts its transport activity by sensing the cytoplasmic K(+) concentration as a measure for hyperosmotic stress via the osmosensing carboxy-terminal domain. BetP needs to be in a trimeric state for communication between individual protomers through several intratrimeric interaction sites. Recently, crystal structures of inward-facing BetP trimers have contributed to our understanding of activity regulation on a molecular level. Here we report new crystal structures, which reveal two conformationally asymmetric BetP trimers, capturing among them three distinct transport states. We observe a total of four new conformations at once: an outward-open apo and an outward-occluded apo state, and two closed transition states--one in complex with betaine and one substrate-free. On the basis of these new structures, we identified local and global conformational changes in BetP that underlie the molecular transport mechanism, which partially resemble structural changes observed in other sodium-coupled LeuT-like fold transporters, but show differences we attribute to the osmolytic nature of betaine, the exclusive substrate specificity and the regulatory properties of BetP.

PubMed: 22940865
DOI: 10.1038/NATURE11403

実験手法

X-RAY DIFFRACTION (3.1 Å)