2OO5

Structure of transhydrogenase (dI.H2NADH)2(dIII.NADP+)1 asymmetric complex

2OO5 の概要

• エントリーDOI: 10.2210/pdb2oo5/pdb
• 関連するPDBエントリー: 1HZZ 1U2D 2OOR
• 分子名称: NAD(P) transhydrogenase subunit alpha part 1, NAD(P) transhydrogenase subunit beta, SULFATE ION, ... (6 entities in total)
• 機能のキーワード: rossmann fold; nad(h)-binding site; nadp(h)-binding site, oxidoreductase
• 由来する生物種: Rhodospirillum rubrum; 詳細
• 細胞内の位置: Cell inner membrane; Multi-pass membrane protein (By similarity): P0C188
• タンパク質・核酸の鎖数: 3
• 化学式量合計: 101861.60

構造登録者

Bhakta, T.,Jackson, J.B. (登録日: 2007-01-25, 公開日: 2007-03-13, 最終更新日: 2023-08-30)

主引用文献

Bhakta, T.,Whitehead, S.J.,Snaith, J.S.,Dafforn, T.R.,Wilkie, J.,Rajesh, S.,White, S.A.,Jackson, J.B.
Structures of the dI(2)dIII(1) Complex of Proton-Translocating Transhydrogenase with Bound, Inactive Analogues of NADH and NADPH Reveal Active Site Geometries
Biochemistry, 46:3304-3318, 2007

PubMed Abstract: Transhydrogenase couples the redox reaction between NADH and NADP+ to proton translocation across a membrane. The enzyme comprises three components; dI binds NAD(H), dIII binds NADP(H), and dII spans the membrane. The 1,4,5,6-tetrahydro analogue of NADH (designated H2NADH) bound to isolated dI from Rhodospirillum rubrum transhydrogenase with similar affinity to the physiological nucleotide. Binding of either NADH or H2NADH led to closure of the dI mobile loop. The 1,4,5,6-tetrahydro analogue of NADPH (H2NADPH) bound very tightly to isolated R. rubrum dIII, but the rate constant for dissociation was greater than that for NADPH. The replacement of NADP+ on dIII either with H2NADPH or with NADPH caused a similar set of chemical shift alterations, signifying an equivalent conformational change. Despite similar binding properties to the natural nucleotides, neither H2NADH nor H2NADPH could serve as a hydride donor in transhydrogenation reactions. Mixtures of dI and dIII form dI2dIII1 complexes. The nucleotide charge distribution of complexes loaded either with H2NADH and NADP+ or with NAD+ and H2NADPH should more closely mimic the ground states for forward and reverse hydride transfer, respectively, than previously studied dead-end species. Crystal structures of such complexes at 2.6 and 2.3 A resolution are described. A transition state for hydride transfer between dihydronicotinamide and nicotinamide derivatives determined in ab initio quantum mechanical calculations resembles the organization of nucleotides in the transhydrogenase active site in the crystal structure. Molecular dynamics simulations of the enzyme indicate that the (dihydro)nicotinamide rings remain close to a ground state for hydride transfer throughout a 1.4 ns trajectory.

PubMed: 17323922
DOI: 10.1021/bi061843r

実験手法

X-RAY DIFFRACTION (2.6 Å)