7MDH

STRUCTURAL BASIS FOR LIGHT ACITVATION OF A CHLOROPLAST ENZYME. THE STRUCTURE OF SORGHUM NADP-MALATE DEHYDROGENASE IN ITS OXIDIZED FORM

7MDH の概要

• エントリーDOI: 10.2210/pdb7mdh/pdb
• 分子名称: PROTEIN (MALATE DEHYDROGENASE), ZINC ION (3 entities in total)
• 機能のキーワード: chloroplastic malate dehydrogenase (nadp+), activated by light, chloroplastic malate dehydrogenase
• 由来する生物種: Sorghum bicolor (sorghum)
• 細胞内の位置: Plastid, chloroplast: P17606
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 164577.66

構造登録者

Johansson, K.,Ramaswamy, S.,Saarinen, M.,Lemaire-Chamley, M.,Issakidis-Bourguet, E.,Miginiac-Maslow, M.,Eklund, H. (登録日: 1999-02-16, 公開日: 1999-06-04, 最終更新日: 2024-10-30)

主引用文献

Johansson, K.,Ramaswamy, S.,Saarinen, M.,Lemaire-Chamley, M.,Issakidis-Bourguet, E.,Miginiac-Maslow, M.,Eklund, H.
Structural basis for light activation of a chloroplast enzyme: the structure of sorghum NADP-malate dehydrogenase in its oxidized form.
Biochemistry, 38:4319-4326, 1999

PubMed Abstract: Some key chloroplast enzymes are activated by light via a ferredoxin-thioredoxin reduction system which reduces disulfide bridges in the enzymes. We describe for the first time the structural basis for the redox activation of a chloroplast enzyme, the NADP-dependent malate dehydrogenase (MDH) from Sorghum vulgare whose structure has been determined and refined at 2.4 A resolution. In addition to the normal structural components of MDHs, the enzyme exhibits extensions at both the N- and C-termini, each of which contains a regulatory disulfide bridge which must be reduced for activation. The N-terminal disulfide motif is inserted in a cleft between the two subunits of the dimer, thereby locking the domains in each subunit. The C-terminal disulfide keeps the C-terminal residues tight to the enzyme surface and blocks access to the active site. Reduction of the N-terminal disulfide would release the stopper between the domains and give the enzyme the necessary flexibility. Simultaneous reduction of the C-terminal disulfide would free the C-terminal residues from binding to the enzyme and make the active site accessible.

PubMed: 10194350
DOI: 10.1021/bi982876c

実験手法

X-RAY DIFFRACTION (2.4 Å)