5CPT

Disproportionating enzyme 1 from Arabidopsis - beta cyclodextrin soak

5CPT の概要

• エントリーDOI: 10.2210/pdb5cpt/pdb
• 関連するBIRD辞書のPRD_ID: PRD_900018
• 分子名称: 4-alpha-glucanotransferase DPE1, chloroplastic/amyloplastic, alpha-D-glucopyranose-(1-4)-beta-D-glucopyranose, 1,2-ETHANEDIOL, ... (4 entities in total)
• 機能のキーワード: disproportionating enzyme 1, 4-alpha-glucanotransferase, glycoside hydrolase family 77, starch degradation, transferase
• 由来する生物種: Arabidopsis thaliana (Mouse-ear cress)
• 細胞内の位置: Plastid, chloroplast: Q9LV91
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 128318.06

構造登録者

O'Neill, E.C.,Stevenson, C.E.M.,Tantanarat, K.,Latousakis, D.,Donaldson, M.I.,Rejzek, M.,Limpaseni, T.,Smith, A.M.,Field, R.A.,Lawson, D.M. (登録日: 2015-07-21, 公開日: 2015-11-04, 最終更新日: 2024-10-23)

主引用文献

O'Neill, E.C.,Stevenson, C.E.,Tantanarat, K.,Latousakis, D.,Donaldson, M.I.,Rejzek, M.,Nepogodiev, S.A.,Limpaseni, T.,Field, R.A.,Lawson, D.M.
Structural Dissection of the Maltodextrin Disproportionation Cycle of the Arabidopsis Plastidial Disproportionating Enzyme 1 (DPE1).
J.Biol.Chem., 290:29834-29853, 2015

PubMed Abstract: The degradation of transitory starch in the chloroplast to provide fuel for the plant during the night requires a suite of enzymes that generate a series of short chain linear glucans. However, glucans of less than four glucose units are no longer substrates for these enzymes, whereas export from the plastid is only possible in the form of either maltose or glucose. In order to make use of maltotriose, which would otherwise accumulate, disproportionating enzyme 1 (DPE1; a 4-α-glucanotransferase) converts two molecules of maltotriose to a molecule of maltopentaose, which can now be acted on by the degradative enzymes, and one molecule of glucose that can be exported. We have determined the structure of the Arabidopsis plastidial DPE1 (AtDPE1), and, through ligand soaking experiments, we have trapped the enzyme in a variety of conformational states. AtDPE1 forms a homodimer with a deep, long, and open-ended active site canyon contained within each subunit. The canyon is divided into donor and acceptor sites with the catalytic residues at their junction; a number of loops around the active site adopt different conformations dependent on the occupancy of these sites. The "gate" is the most dynamic loop and appears to play a role in substrate capture, in particular in the binding of the acceptor molecule. Subtle changes in the configuration of the active site residues may prevent undesirable reactions or abortive hydrolysis of the covalently bound enzyme-substrate intermediate. Together, these observations allow us to delineate the complete AtDPE1 disproportionation cycle in structural terms.

PubMed: 26504082
DOI: 10.1074/jbc.M115.682245

実験手法

X-RAY DIFFRACTION (2.3 Å)