6QUE

Structure of ovine transhydrogenase in the presence of NADP+ in a "single face-down" conformation

6QUE の概要

• エントリーDOI: 10.2210/pdb6que/pdb
• 関連するPDBエントリー: 6QTI
• EMDBエントリー: 4637
• 分子名称: Nicotinamide nucleotide transhydrogenase, NADP NICOTINAMIDE-ADENINE-DINUCLEOTIDE PHOSPHATE, NICOTINAMIDE-ADENINE-DINUCLEOTIDE (3 entities in total)
• 機能のキーワード: mitochondrial, proton-translocating, nicotinamide nucleotide transhydrogenase, membrane protein
• 由来する生物種: Ovis aries (Sheep)
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 230030.80

構造登録者

Kampjut, D.,Sazanov, L.A. (登録日: 2019-02-27, 公開日: 2019-08-28, 最終更新日: 2024-05-15)

主引用文献

Kampjut, D.,Sazanov, L.A.
Structure and mechanism of mitochondrial proton-translocating transhydrogenase.
Nature, 573:291-295, 2019

PubMed Abstract: Proton-translocating transhydrogenase (also known as nicotinamide nucleotide transhydrogenase (NNT)) is found in the plasma membranes of bacteria and the inner mitochondrial membranes of eukaryotes. NNT catalyses the transfer of a hydride between NADH and NADP, coupled to the translocation of one proton across the membrane. Its main physiological function is the generation of NADPH, which is a substrate in anabolic reactions and a regulator of oxidative status; however, NNT may also fine-tune the Krebs cycle. NNT deficiency causes familial glucocorticoid deficiency in humans and metabolic abnormalities in mice, similar to those observed in type II diabetes. The catalytic mechanism of NNT has been proposed to involve a rotation of around 180° of the entire NADP(H)-binding domain that alternately participates in hydride transfer and proton-channel gating. However, owing to the lack of high-resolution structures of intact NNT, the details of this process remain unclear. Here we present the cryo-electron microscopy structure of intact mammalian NNT in different conformational states. We show how the NADP(H)-binding domain opens the proton channel to the opposite sides of the membrane, and we provide structures of these two states. We also describe the catalytically important interfaces and linkers between the membrane and the soluble domains and their roles in nucleotide exchange. These structures enable us to propose a revised mechanism for a coupling process in NNT that is consistent with a large body of previous biochemical work. Our results are relevant to the development of currently unavailable NNT inhibitors, which may have therapeutic potential in ischaemia reperfusion injury, metabolic syndrome and some cancers.

PubMed: 31462775
DOI: 10.1038/s41586-019-1519-2

実験手法

ELECTRON MICROSCOPY (3.7 Å)